Miscarriage & Recurrent Pregnancy Loss

Overview & Definition

Miscarriage, or spontaneous abortion, is the spontaneous loss of a pregnancy before the fetus reaches viability. In UK practice that includes all pregnancy losses from conception until 24 weeks of gestation. US reviews of early bleeding commonly use a 20-week threshold. An estimated 23 million miscarriages occur every year worldwide (44 losses each minute), with a pooled risk of 15.3 percent (95 percent CI 12.5 to 18.7) of recognised pregnancies. The population prevalence of women who have had one miscarriage is 10.8 percent, two is 1.9 percent, and three or more is 0.7 percent. Losses are conventionally divided into early (first-trimester) — the large majority — and late (second-trimester), which have a different cause profile and carry greater maternal risk.^[2][3]

The topic is high-yield because of four examinable pillars. First, the classification (threatened, inevitable, incomplete, complete, missed, septic) is decided by the cervical os and by ultrasound viability — a classic viva and MCQ discriminator. Second, the transvaginal ultrasound criteria for non-viability are explicit and must never be misapplied, because a false-positive diagnosis of loss can lead to the destruction of a wanted, viable pregnancy. Third, the three management options (expectant, medical, surgical) are genuinely equivalent in outcome, so patient choice drives selection. Fourth, recurrent pregnancy loss has a structured workup whose centrepiece — antiphospholipid syndrome — is the one cause with a proven, treatable answer. Running through all of it is the clinical skill of compassionate communication: most women blame themselves, and the reassurance that the commonest cause is a random, non-recurrent chromosomal error is itself therapeutic.^[17][17]

A clinically useful distinction is the PUL — pregnancy of unknown location. When a woman bleeds in early pregnancy and the initial TVS shows neither an intrauterine nor an ectopic pregnancy, the pregnancy is of unknown location until serial hCG and repeat imaging resolve it. This framing protects against two errors: declaring a loss prematurely, and missing an ectopic. ^[7]

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Classification

The clinical types of miscarriage are distinguished by two findings at speculum examination — the cervical os (open or closed) — combined with what has been passed and the ultrasound appearance. Getting this classification right determines management, and it is the single most frequently tested fact in the topic. ^[10]

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A threatened miscarriage with a documented fetal heartbeat has a better prognosis than bleeding without a heartbeat; still safety-net for heavier bleeding, fever, or pain. An inevitable or incomplete miscarriage is the typical acute presentation needing assessment for blood loss and a decision on evacuation. A missed miscarriage is often an ultrasound surprise at a routine scan, which makes the repeat-scan rule (below) so important. Septic miscarriage is now rare where safe services exist but remains an obstetric emergency where unsafe procedures are performed. ^[10]

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Recurrent pregnancy loss (RPL)

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RCOG figures put recurrent miscarriage (three or more consecutive losses) at 1 percent of couples trying to conceive. Population data put the prevalence of women who have had three or more miscarriages at 0.7 percent and two at 1.9 percent. ESHRE's 2017 guideline explicitly notes the absence of evidence for a single definition of RPL. ^{[23][24][14][27]}

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Epidemiology & Risk Factors

The single strongest determinant of miscarriage risk is maternal age, driven by the rising rate of oocyte aneuploidy. In Nybo Andersen's Danish register, the risk of spontaneous abortion was 8.9 percent at age 20 to 24 years and 74.7 percent at 45 years or more, and more than half of pregnancies intended to be carried to term ended in fetal loss at age 42. RCOG Green-top 17 quotes the same register's recognised-pregnancy ladder: 12 percent at 25 to 29 years, 25 percent at 35 to 39, 51 percent at 40 to 44, and 93 percent at 45 or older. The biological basis is that female oocytes arrest in prophase of meiosis I before birth and resume division decades later; the longer the oocyte is held in arrest, the more the meiotic spindle and cohesion complex degrade, so that nondisjunction — and therefore aneuploidy — becomes steadily more likely. Paternal age over 40 contributes a smaller additional risk through rising sperm aneuploidy and DNA fragmentation. ^[25][23][20]

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Risk factors group logically into maternal, anatomic, endocrine, thrombophilic, infectious, lifestyle and iatrogenic categories: ^[17]

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• Maternal age — the dominant factor (see above); also a predictor of recurrence.
• Previous miscarriage — risk rises with each successive loss; RCOG Green-top 17 reports that the risk of a further miscarriage reaches approximately 40 percent after three consecutive pregnancy losses.
• Anatomic — congenital uterine anomalies (septum is the one most strongly linked to loss), diethylstilboestrol exposure in utero, cervical insufficiency, submucosal fibroids, intrauterine adhesions (Asherman).
• Endocrine — uncontrolled type 1 or type 2 diabetes (HbA1c elevated pre-conception), thyroid disease, polycystic ovary syndrome, poorly controlled hyperprolactinaemia.
• Thrombophilic — antiphospholipid syndrome (acquired), and inherited thrombophilias (factor V Leiden, prothrombin gene mutation, protein C/S and antithrombin deficiency), particularly linked to late loss.
• Infectious — listeria, toxoplasma, syphilis, malaria, brucella; often modifiable.
• Lifestyle and environment — smoking, alcohol, obesity, high caffeine intake, and recreational drugs are listed as associated factors; GTG 17 notes that smoking and caffeine evidence is conflicting and biased by exposure measurement.
• Iatrogenic — teratogenic drugs (warfarin, retinoids, methotrexate, some anticonvulsants), invasive prenatal procedures. ^[17]

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Importantly, a single first-trimester loss is usually a sporadic chromosomal event — recurrence risk is low, and most women go on to a successful next pregnancy. This single fact is the cornerstone of post-miscarriage counselling. ^[1]

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Aetiology

Miscarriage is usually the result of interplay between embryo, endometrium, placental perfusion, and maternal health. The relative importance of each cause shifts with gestational age, maternal age, and whether the loss is sporadic or recurrent. A systematic aetiological framework is essential for counselling and for directing investigation in recurrent loss. ^[1]

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Chromosomal abnormalities

Chromosomal abnormalities of the conceptus are the single largest cause of first-trimester miscarriage. In 1,745 spontaneous losses, 50.4 percent of products of conception were karyotypically abnormal; adding haplarithmisis-detected cryptic aberrations raised the estimated rate to 67.8 percent. The spectrum is dominated by autosomal trisomies, monosomy X, triploidy, and structural rearrangements inherited from a balanced translocation carrier. Most numerical errors arise from meiotic nondisjunction in the maternal oocyte, reflecting the biology of an oocyte arrested in prophase I for years. The error is usually non-recurrent, which is why a single chromosomal loss carries a good prognosis.^[1]

Uterine and cervical factors

Congenital uterine anomalies are found in up to 20 percent of women with recurrent miscarriage, and the septate uterus is the anomaly most strongly linked to first-trimester loss. Other anatomic causes include submucosal fibroids, intrauterine adhesions (Asherman syndrome), and cervical insufficiency — the latter presenting with painless second-trimester dilation. Acquired uterine cavity disease from previous surgery, infection, or over-vigorous curettage can also compromise implantation and placental bed development.^[17]

Endocrine and metabolic disease

Uncontrolled diabetes, thyroid disease (hypothyroidism and hyperthyroidism), hyperprolactinaemia, and polycystic ovary syndrome can all increase miscarriage risk. The mechanism is often a combination of poor pre-implantation endometrial quality, luteal-phase progesterone deficiency, and altered early vascular adaptation. Optimising metabolic control before conception is one of the most effective interventions; an HbA1c in the target range before pregnancy reduces both aneuploidy-independent and pregnancy complication risk.^[17]

Immunological and thrombophilic causes

Antiphospholipid syndrome (APS) is the most important treatable acquired cause of recurrent miscarriage. It is diagnosed by persistent lupus anticoagulant, anticardiolipin, or anti-beta-2-glycoprotein-I antibodies, and acts by causing placental microvascular thrombosis and infarction. Inherited thrombophilias (factor V Leiden, prothrombin gene mutation, protein C, protein S, and antithrombin deficiency) are more strongly associated with late first-trimester and second-trimester losses, but routine screening is not recommended in uncomplicated recurrent loss because trial evidence has not shown benefit from heparin in unselected cases.^[12]

Infection and environmental exposures

Systemic infections such as listeria, toxoplasmosis, syphilis, malaria, brucella, and parvovirus B19 can precipitate miscarriage, particularly in endemic areas or immunocompromised hosts. Local genital-tract infection and chronic endometritis are active areas of research in recurrent loss. Lifestyle factors independently raise risk: smoking approximately doubles the risk, and heavy alcohol use, obesity, high caffeine intake, and recreational drugs also contribute. Ionising radiation, certain solvents, and teratogenic drugs (warfarin, retinoids, methotrexate, some anticonvulsants) can cause loss.^[17]

A note on causation

After one or even two losses, it is often impossible to assign a specific cause. In recurrent loss, the diagnostic yield of the standard workup is only about 50 to 60 percent; the remainder is classified as unexplained. Even in unexplained recurrent loss, the prognosis remains good with supportive care, so counselling should be balanced and hopeful.^[17]

Pathophysiology

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Successful early pregnancy depends on three integrated processes — a euploid embryo, an adequately remodelling decidua and spiral artery bed, and a functioning placental endocrine unit (hCG and progesterone) — held in immunological tolerance by the maternal-fetal interface. Miscarriage results when any of these fails. ^[17]

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Chromosomal abnormalities — the dominant mechanism

Chromosomal abnormalities of the conceptus are the commonest cause — 50.4 percent on standard karyotype of products of conception, 67.8 percent after accounting for cryptic lineage-specific aberrations. They fall into several recognisable patterns: ^[20]

^[1]

• Autosomal trisomies are the largest group. Trisomy 16 is the single most frequent and is virtually always lethal; trisomies of 21, 18, 13, 22 and 15 are also common. Most arise from meiotic nondisjunction — failure of homologous chromosomes (meiosis I) or sister chromatids (meiosis II) to separate, producing a gamete with an extra chromosome. The error is usually maternal, in the oocyte.
• Monosomy X (45,X, Turner syndrome) is the commonest single chromosomal abnormality in early loss. It typically arises from loss of the paternal sex chromosome; it is the only viable human monosomy, but the great majority of 45,X conceptions are lost in the first trimester.
• Triploidy (69,XXX/XXY/XYY) — three full sets of chromosomes, often from diandry (dispermy — two sperm fertilising one oocyte) or digyny (a diploid oocyte). Diandric triploidy gives a partial mole appearance with an enlarged placenta; digynic triploidy gives a small placenta and growth-restricted fetus.
• Tetraploidy (92,XXXX) — usually lethal and a post-zygotic error.
• Structural rearrangements — a small but important minority (3 to 5 percent of couples with RPL) carry a balanced parental translocation (reciprocal or Robertsonian). The parent is phenotypically normal, but gametes receive an unbalanced complement, producing recurrent losses or live-born children with congenital abnormalities (for example, Down syndrome from a Robertsonian translocation). ^[1]

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The consequence of a lethal chromosomal error is embryonic developmental arrest. The embryo may never form (an anembryonic gestation or blighted ovum — a gestational sac with a yolk sac but no embryo), or it may form and then stop growing and lose its heartbeat (an embryonic or fetal missed loss). On ultrasound the gestational sac becomes irregular or empty, its margins become distorted, and the pregnancy resolves as the trophoblast fails. ^[1]

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Decidual separation and bleeding

Once the trophoblast and decidua begin to separate from the uterine wall, the maternal decidual sinusoids are opened, producing the vaginal bleeding that brings the woman to care. Uterine contractions — felt as cramping — accompany the expulsion of products. In an incomplete loss, retained tissue keeps the cervix open and the bleeding ongoing; in a complete loss, the uterus contracts down, the os closes, and bleeding settles. The amount of blood lost can be substantial, and the haemodynamic picture (tachycardia, hypotension) rather than the reported volume should guide resuscitation. ^[17]

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Placental endocrine failure — hCG and progesterone

A viable early pregnancy is sustained by human chorionic gonadotrophin (hCG), produced by the syncytiotrophoblast, which rescues the corpus luteum and maintains progesterone secretion until the luteoplacental shift at around 7 to 10 weeks. Progesterone is the hormone of pregnancy maintenance — it stabilises the decidual endometrium, suppresses uterine contractility, and modulates the maternal immune response. When an embryo is non-viable, hCG production falls, progesterone support is withdrawn, and the decidua breaks down. This endocrine logic underpins serial hCG interpretation in pregnancy of unknown location: NICE uses a greater than 63 percent rise in 48 hours as the threshold at which a developing intrauterine pregnancy is likely (ectopic still not excluded), and a greater than 50 percent fall as indicating the pregnancy is unlikely to continue. Do not use serum progesterone as an adjunct to diagnose viable intrauterine pregnancy or ectopic pregnancy in PUL. The same endocrine logic explains mifepristone in medical management of missed miscarriage — a progesterone-receptor antagonist given 48 hours before misoprostol. ^[22]

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Spiral artery remodelling and placental thrombosis

For a pregnancy to progress beyond the first trimester, the extravillous trophoblast must invade and remodel the maternal spiral arteries, converting them from narrow, high-resistance vessels into dilated, low-resistance channels that deliver the increasing blood flow the fetus demands. When this remodelling fails — as in antiphospholipid syndrome, inherited thrombophilias, or severe hypertensive disease — the placental bed suffers microvascular thrombosis and infarction, placental perfusion falls, and the pregnancy fails, often in the late first or second trimester. This is the placental mechanism that links thrombophilia to recurrent and late loss, and it is why anticoagulation can improve outcome in APS-related RPL. ^[17]

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Immunological tolerance

Pregnancy is a natural allograft — the fetus carries paternal antigens yet is not rejected. Tolerance depends on HLA-G expression by the trophoblast (which protects it from maternal cytotoxic T cells), on a balanced population of uterine natural killer cells, and on regulatory T-cell activity. Disturbances in these mechanisms are an active area of research in unexplained RPL, though no single immunological test yet has a proven treatment attached to it. ^[17]

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Late-loss mechanisms

Late (second-trimester) losses have a distinct mechanism profile: cervical insufficiency (painless dilation with bulging membranes, from a congenital, traumatic — cone biopsy/LEEP — or iatrogenic cause), major uterine anomalies (septum), severe maternal infection (e.g. chorioamnionitis), placental abruption, and antiphospholipid syndrome with placental thrombosis. These mechanisms are why the RPL workup emphasises uterine anatomy and the thrombophilias.^[17]

Clinical Presentation

The classic presentation is vaginal bleeding with lower abdominal cramping in a woman who knows or suspects she is pregnant. The amount of bleeding ranges from light spotting to heavy loss with clots and tissue. Pain is usually central and cramping in character, which helps distinguish miscarriage from the lateral, often shoulder-tip, pain of a ruptured ectopic. Specific features define each type: ^[10]

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• Threatened — lighter bleeding, closed os, viable fetus on scan; pregnancy symptoms (nausea, breast tenderness, urinary frequency) preserved. About 1 in 4 women bleed at some point in early pregnancy and most continue.
• Inevitable — moderate to heavy bleeding with cramping; os open; products not yet passed. The woman often describes the bleeding as heavier than a period.
• Incomplete — partial passage of tissue (she may describe "something coming away"), open os, ongoing or heavy bleeding; the commonest presentation needing acute care.
• Complete — all products passed; bleeding and pain settling; os closed. The woman often reports that the pain resolved once tissue passed.
• Missed — often a routine-scan finding; the woman reports loss of pregnancy symptoms (nausea gone, breasts no longer tender) but may have minimal or no bleeding.
• Septic — fever, pelvic/abdominal pain, foul-smelling vaginal discharge, uterine tenderness, tachycardia; a history of an unsafe procedure is the key clue. ^[10]

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Atypical presentations examiners test deliberately: ^[10]

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• Unrecognised or unplanned pregnancy — a woman may attribute early heavy bleeding to a late, heavy period (a biochemical or "chemical" pregnancy loss, detectable only on a pregnancy test around the time of the expected period).
• Older women — higher baseline miscarriage risk, more comorbidity, and often a long path to conception with IVF; the psychological stakes are high.
• IVF pregnancies — higher early-loss rate and greater emotional investment; an early scan is routine.
• Women on anticoagulation or with a bleeding diathesis — bleeding may be heavier and management must coordinate the haematological and obstetric issues.
• A woman who presents in shock — assume a ruptured ectopic or sepsis until proven otherwise; resuscitate first, investigate second. ^[10]

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Interpreting pain, bleeding and haemodynamics

The character of pain and the volume of bleeding are useful, but they are not definitive. A woman with a threatened miscarriage can pass surprisingly large clots, while a missed miscarriage can be entirely silent. What matters is the clinical trajectory. ^[10]

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• Threatened miscarriage is usually described as light spotting, often brownish, with mild cramping. About one in four women has some first-trimester bleeding; once a live embryo with a heartbeat is seen on scan, the majority continue to term. Still, the woman must be safety-netted: a threatened miscarriage can evolve into an inevitable or incomplete loss, and Rh-negative women need anti-D.
• Inevitable and incomplete miscarriage are the classic acute presentations. Bleeding is usually heavier than a period, bright red, and accompanied by clots and tissue. Pain is central, cramping, and may come in waves as the uterus contracts. The open cervical os tells you that the process is active and cannot be stopped. Haemodynamic instability — tachycardia, postural drop, or hypotension — means the bleeding is significant and surgical evacuation is needed.
• Missed miscarriage is often discovered when symptoms of pregnancy regress. A woman may say her nausea has gone, her breasts are no longer tender, or she has lost the metallic taste in her mouth. Because there is no active bleeding, the diagnosis rests on ultrasound, and the repeat-scan rule is essential to avoid a false-positive diagnosis of loss.
• Septic miscarriage should be suspected when there is fever, tachycardia, uterine tenderness, and foul discharge, especially after an unsafe termination or instrumentation. The woman may have been unwell for days before seeking care. This is an emergency: sepsis can progress rapidly to septic shock, acute respiratory distress syndrome, and disseminated intravascular coagulation. ^[10]

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Two practical rules always apply: assess the haemodynamic status before taking a long history, and never assume a closed os means the bleeding is not serious. A closed os with a viable fetus is reassuring, but a closed os with retained infected products can still cause sepsis, and a closed os in an ectopic pregnancy is the most dangerous situation of all. The cervical os is the single most reliable clinical sign; do not be misled by the amount of blood alone, and always confirm the diagnosis with transvaginal ultrasound when bleeding occurs in early pregnancy. ^[10]

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Differential Diagnosis

Every woman with bleeding in early pregnancy must be assumed to have a pregnancy of unknown location until a viable intrauterine pregnancy is confirmed — because the differential contains a life-threatening mimic (ectopic) and several look-alikes. ^[7]

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The pivotal reflex is: bleeding in early pregnancy equals TVS to locate the pregnancy and exclude ectopic, supported by a serial quantitative beta-hCG. The distinguishing features are the character of the pain (central/cramping in miscarriage vs lateral/constant or shoulder-tip in ectopic), the volume of bleeding (heavy with products in miscarriage vs dark and scanty in ectopic), and the ultrasound (intrauterine vs empty uterus with an adnexal mass). ^[7]

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Clinical & Bedside Assessment

Begin with ABCs and haemodynamic status — tachycardia, hypotension and pallor signal significant bleeding or sepsis and demand resuscitation rather than a prolonged history. Tachycardia and postural drop are early signs; hypotension is late. Focused assessment then covers: ^[10]

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• History — last menstrual period and gestation; the amount of bleeding (pads per hour, presence of clots, tissue passed); pain (site, character, severity); obstetric history including previous losses and their gestation; Rh status; medical conditions (diabetes, thyroid, APS, thrombophilia); medications (especially anticoagulants and teratogens); and any history of an unsafe procedure.
• Speculum examination — assess the cervical os (open or closed: the classification hinge); the source and volume of bleeding; whether products of conception are visible at the os (and remove them gently, as this alone may reduce bleeding); and exclude local cervical causes (polyp, ectropion, trauma).
• Bimanual examination — uterine size and tenderness, adnexal masses or tenderness, and cervical excitation (pain on moving the cervix, which raises the suspicion of ectopic or PID). ^[10]

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Findings are then interpreted together with a transvaginal ultrasound. A tender, boggy uterus with an open os and heavy bleeding points to incomplete miscarriage; a closed os with a viable fetus points to threatened loss; a tender uterus with fever and discharge is septic until proven otherwise. In a shocked patient, resuscitate first and image in parallel or after — never delay life-saving surgery (for a suspected ruptured ectopic) for a scan. ^[10]

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Investigations

Transvaginal ultrasound (TVS) — the diagnostic cornerstone

TVS determines whether a pregnancy is intrauterine, whether it is viable, and what has been passed or retained. To avoid the catastrophic error of declaring a viable pregnancy non-viable, the current international consensus criteria — adopted across US, UK and Australian guidelines after the 2011 evidence review — set conservative size cut-offs that must never be applied to a single isolated measurement when there is any doubt: ^[5][6]

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The discriminatory zone is a serum hCG threshold above which an intrauterine pregnancy is expected to be visible on transvaginal ultrasound. Condous and colleagues evaluated greater than 1000, 1500 and 2000 IU/L in women with PUL: sensitivity for ectopic pregnancy was only 21.7 percent, 15.2 percent and 10.9 percent respectively. A single hCG measurement does not exclude ectopic pregnancy and should not be used as a location test.^[7]

Serial beta-hCG

A quantitative serum beta-hCG is interpreted dynamically, never as a single value, and NICE does not use hCG to determine pregnancy location. Take two measurements as near as possible to 48 hours apart. An increase greater than 63 percent after 48 hours means she is likely to have a developing intrauterine pregnancy (ectopic is not excluded). A decrease greater than 50 percent means the pregnancy is unlikely to continue but does not confirm location. Do not use serum progesterone as an adjunct to diagnose viable intrauterine pregnancy or ectopic pregnancy in PUL.^[22]

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Scan-hCG concordance and the pregnancy of unknown location

When the ultrasound is inconclusive, the relationship between the scan and the quantitative hCG becomes the decision map: ^[7]

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• If the uterus is empty on TVS, classify the pregnancy as a pregnancy of unknown location (PUL) and work it up with serial hCG and repeat scanning rather than assuming miscarriage.^[7]
• Evaluated discriminatory-zone cut-offs of greater than 1000, 1500 and 2000 IU/L have low sensitivity for ectopic pregnancy in a PUL population (21.7 to 10.9 percent) — do not use a single hCG to exclude ectopic.^[7]
• If the hCG falls, the pregnancy is failing regardless of location; falling hCG with an empty uterus can still represent a resolving ectopic or an intrauterine miscarriage that has already passed. ^[7]

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Pitfalls to avoid: ^[7]

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• Do not diagnose miscarriage from a single hCG value.
• Do not diagnose miscarriage from a single borderline scan — repeat the scan before declaring non-viability.
• Do not discharge a woman with a PUL without a clear plan for serial hCG and repeat imaging.
• Remember that multiple pregnancy can produce higher hCG for gestational age and may show more than one gestational sac. ^[7]

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Bloods and microbiology

• Full blood count — to assess anaemia, the platelet count, and (in sepsis) the white-cell count.
• Group and save / crossmatch — if bleeding is heavy or the woman is Rh-negative (to plan anti-D and, if needed, transfusion).
• Blood cultures, CRP, high vaginal swab — if septic miscarriage is suspected.
• Coagulation screen — in heavy bleeding or suspected sepsis, to detect incipient DIC. ^[10]

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Histopathology

Any tissue passed or evacuated should be sent for histology to confirm products of conception and to exclude molar pregnancy (which changes follow-up dramatically). In RPL, karyotyping of the products (by array comparative genomic hybridisation or QF-PCR) can reveal whether a loss was due to aneuploidy — useful prognostically and for counselling. ^[20]

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Recurrent pregnancy loss workup

After 2 to 3 consecutive losses the structured workup is: ^[10]

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• Parental peripheral blood karyotype — to detect a balanced reciprocal or Robertsonian translocation (3 to 5 percent of couples with RPL).
• Antiphospholipid antibodies — lupus anticoagulant, anticardiolipin (IgG/IgM), and anti-beta-2-glycoprotein-I, repeated at 12 weeks to confirm persistence (the APS laboratory criteria).
• Uterine assessment — 3D pelvic ultrasound, saline infusion sonohysterography, or hysteroscopy to detect a septum or other anomaly; hysterosalpingography if tubal assessment is also needed.
• Endocrine — TSH and HbA1c; consider prolactin and a PCOS screen.
• Inherited thrombophilia screen — factor V Leiden, prothrombin gene mutation, protein C, protein S, antithrombin (especially after a late loss).
• Karyotype of products, where available, from any future loss. ^[20]

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Management — Resuscitation

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The immediate, time-critical bundles address the two emergencies — haemorrhage and sepsis: ^[10]

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Management — Definitive & Stepwise

Threatened miscarriage

Advise women with a confirmed intrauterine pregnancy, a fetal heartbeat, bleeding, and no previous miscarriage that if bleeding gets worse or persists beyond 14 days they should return, and that if it stops they should continue routine antenatal care. Offer vaginal micronised progesterone 400 mg twice daily to women with a scan-confirmed intrauterine pregnancy, vaginal bleeding, and a previous miscarriage; if a fetal heartbeat is confirmed, continue progesterone until 16 completed weeks. Traditional restrictions on intercourse, travel, and bed rest are not evidence-based. Do not offer anti-D up to and including 11+6 weeks (NICE 2026). Document a clear safety-net. ^[22]

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Missed, inevitable or incomplete miscarriage (stable)

NICE NG126 uses expectant management for 7 to 14 days as the first-line strategy for a confirmed miscarriage, then explores other options if the woman is at increased risk of haemorrhage (for example late first trimester), has a previous adverse or traumatic pregnancy experience, is at increased risk from haemorrhage (coagulopathy or unable to have a blood transfusion), or there is infection — or if expectant care is not acceptable. Counsel on success rates, the expected experience, follow-up, and surgical risks: ^[22][9]

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1. Expectant (NICE first-line, 7 to 14 days) — most women need no further treatment. In the MIST trial (1,200 women), confirmed gynaecological infection within 14 days was 3 percent after expectant and 3 percent after surgical management (medical 2 percent) — no difference — but expectant care had significantly more unplanned admissions and unplanned surgical curettage.^[9][22]
2. Medical, missed miscarriage — mifepristone 200 mg orally and 48 hours later misoprostol 800 micrograms (vaginal, oral, or sublingual), unless the sac has already passed (NICE 1.11.1; MifeMiso). Mifepristone plus misoprostol reduced failure to pass the sac within 7 days (17 percent vs 24 percent, RR 0.73) and surgical intervention (17 percent vs 25 percent, RR 0.71). Provide analgesia and antiemetics.^[8][22]
3. Medical, incomplete miscarriage — single-dose misoprostol 600 micrograms (800 micrograms is an allowed alternative). Do not offer mifepristone for incomplete miscarriage.^[22]
4. Surgical — uterine evacuation by suction. Needed for heavy bleeding or infection, or when the woman declines expectant/medical care. Clinically unstable patients require urgent procedural management.^[22]

Surgical techniques and safety ^[9]

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Surgical management is the default when bleeding is heavy, infection is present, or expectant/medical management has failed. It is also the right choice when a woman wants a rapid, controlled resolution. The standard operation is uterine evacuation by suction rather than sharp curettage, because suction is quicker, safer, and less likely to cause Asherman syndrome. ^[9]

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• Electric vacuum aspiration (EVA) uses a powered suction pump and is usually performed under general or regional anaesthesia in an operating theatre. It is appropriate for any first-trimester loss, including those with heavier bleeding or more substantial tissue.
• Manual vacuum aspiration (MVA) uses a handheld syringe to generate suction. It can be performed in the outpatient or clinic setting under local anaesthetic with oral analgesia. MVA is effective for pregnancies up to around 12 weeks, has low complication rates, and avoids the risks of general anaesthesia. It is the preferred surgical option in many low-resource settings.
• Dilatation and curettage (D&C) with a sharp curette is now discouraged for first-trimester evacuation because it carries a higher risk of uterine perforation, infection, and intrauterine adhesions. Suction is preferred for routine management. ^[9]

^[9]

Cervical priming with misoprostol 400 to 800 microgram vaginally or sublingually 1 to 3 hours before surgery softens the cervix and reduces cervical trauma, especially in nulliparous women. It is particularly helpful when the pregnancy is over 10 weeks or when the cervix is unfavourable. ^[9]

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After evacuation, all tissue should be sent for histology. A follow-up visit or scan is arranged to confirm that the uterus is empty; if products remain, repeat evacuation or medical treatment may be needed. ^[9]

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Whichever path is chosen: anti-D according to NICE NG126 2026 (do not offer up to 11+6 weeks; offer at least 250 IU at 12+0 to 12+6 if medical or surgical management), adequate analgesia, and follow-up. Expectant and medical arms of MIST both carried more unplanned interventions than surgery.^[22][9][15]

Complete miscarriage

Confirm on history and scan; no further treatment is required. Apply NICE anti-D rules (not offered up to 11+6 weeks), give contraception and pre-conception advice (folic acid 0.4 to 0.8 mg daily, optimise chronic disease), and offer follow-up for support. ^[22][21]

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Surgical complications — know them

• Uterine perforation — occurs in roughly 1 to 4 per 1000 evacuations; suspect if there is unexpected pain, bleeding, or visceral injury; manage expectantly if small and stable, laparoscopically or laparotomically if bleeding or organ damage.
• Cervical trauma — reduced by cervical priming (misoprostol) and careful dilatation.
• Haemorrhage — from retained tissue or atony; managed by completing evacuation and uterotonics.
• Infection — post-evacuation endometritis; reduced by aseptic technique; treat with antibiotics.
• Asherman syndrome — intrauterine adhesions from over-vigorous curettage; prevented by using suction rather than sharp curettage and gentle technique.
• Anaesthetic complications — relevant to the woman's fitness for general anaesthesia; an argument for MVA under local anaesthesia in suitable cases. ^[9]

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Recurrent pregnancy loss — treat the cause

• Antiphospholipid syndrome: aspirin plus heparin — the regimen international RPL guidelines agree on. RCOG Green-top 17 reports that aspirin plus unfractionated heparin versus aspirin alone reduces the miscarriage rate by 54 percent (RR 0.46, 95 percent CI 0.29 to 0.71).^[14][23]
• Parental translocation, uterine anomalies (septum), endocrine and immune factors: management targets the identified factor — genetic counselling, hysteroscopic correction of anatomical lesions, and optimisation of endocrine disease — although the evidence for many of these treatments remains limited.^[17]
• Inherited thrombophilia: the ALIFE2 trial showed that LMWH did not improve live-birth rates in women with recurrent miscarriage and inherited thrombophilia compared with standard care (72 percent vs 71 percent live births), and its authors advise against both LMWH use and inherited-thrombophilia screening in recurrent pregnancy loss; aspirin plus LMWH remains appropriate only in confirmed APS.^[12]
• Unexplained RPL: supportive care. For women with scan-confirmed intrauterine pregnancy, bleeding, and a previous miscarriage, NICE offers vaginal micronised progesterone 400 mg twice daily (continue to 16 weeks if a heartbeat is confirmed). That is a threatened-miscarriage indication, not a treatment for unexplained RPL without bleeding: PRISM found no significant overall live-birth increase (75 percent vs 72 percent, RR 1.03, P=0.08), and Cochrane 2025 found progestogen in unexplained recurrent miscarriage probably has little to no effect (miscarriage RR 0.91; live birth RR 1.04).^[22][11][16]

Anti-D Immunoglobulin

UK practice is now governed by NICE NG126 (updated 17 June 2026). A Cochrane review found insufficient randomised evidence (one trial of 48 women with miscarriage at 8 to 24 weeks, treated with 300 microgram anti-D intramuscularly) to generalise prophylaxis, and concluded that practice should follow national guidelines.^[22][15]

^[22]

NICE NG126 (2026) — when not to offer, when to offer

• Do not offer anti-D immunoglobulin for ectopic pregnancy, miscarriage, or threatened miscarriage up to and including 11+6 weeks' gestation. If ultrasound gestation and last-menstrual-period dates disagree, use the ultrasound findings.^[22]
• Offer anti-D at a dose of at least 250 IU (50 micrograms) to RhD-negative women at 12+0 to 12+6 completed weeks who are having medical management or a surgical procedure to manage ectopic pregnancy or miscarriage.^[22]
• Consider anti-D at at least 250 IU (50 micrograms) at 12+0 to 12+6 weeks for threatened miscarriage with heavy or recurrent bleeding.^[22]
• Do not use a Kleihauer test to quantify feto-maternal haemorrhage in this setting.^[22]

The 2026 committee noted a lack of evidence of benefit under 12 weeks and no evidence of a difference in sensitisation between medical and surgical interventions for early ectopic pregnancy or miscarriage.^[22]

Documentation

Record Rh status, whether anti-D was indicated, the dose if given, injection site, and batch number. Anti-D is easily forgotten in the distress of a miscarriage — but offering it below 12 weeks is no longer NICE-recommended.^[22]

Ectopic Pregnancy — the Must-Exclude Differential

A woman with bleeding in early pregnancy is assumed to have a pregnancy of unknown location until a viable intrauterine pregnancy is demonstrated. The most important reason for this rule is to avoid missing an ectopic pregnancy, which is the leading cause of first-trimester maternal death and can present with almost identical symptoms to miscarriage.^[19]

Clinical clues that point to ectopic

• Pain is lateral, constant, or radiating to the shoulder tip (from diaphragmatic irritation by intraperitoneal blood), whereas miscarriage pain is usually central and cramping.
• Bleeding is typically dark and scanty, often described as prune-juice spotting.
• Cervical excitation on bimanual examination is a warning sign.
• Syncope, shoulder-tip pain, or haemodynamic collapse suggest rupture and intraperitoneal bleeding. ^[19]

^[19]

Ultrasound and hCG interpretation

On transvaginal ultrasound, an ectopic pregnancy classically shows an empty uterus with an adnexal mass or free fluid in the pouch of Douglas. Evaluated discriminatory-zone thresholds of greater than 1000, 1500 and 2000 IU/L do not significantly improve ectopic detection in PUL; a single hCG is unhelpful in excluding ectopic pregnancy. Location is an ultrasound diagnosis, with serial hCG used only to assess trophoblastic proliferation.^[7][22]

Serial hCG in suspected ectopic

A healthy intrauterine pregnancy shows an appropriately rising beta-hCG on serial measurement. An ectopic pregnancy usually rises more slowly or may plateau, while a failing intrauterine pregnancy often falls. A single hCG value is never diagnostic — the trend and the scan together determine management. ^[7][19]

^[19]

Practical rule

Never discharge a woman with bleeding in early pregnancy without either confirming a viable intrauterine pregnancy on scan or arranging a clear follow-up plan with serial hCG and repeat imaging. ^[19]

^[19]

Specific Subtypes & Scenarios

Cervical insufficiency

A distinct and surgically remediable cause of late, painless second-trimester loss. The cervix dilates painlessly with bulging or prolapsing membranes in an otherwise well woman, without the contractions of labour. Risk factors are congenital (collagen disorders such as Ehlers-Danlos), traumatic (cone biopsy, LEEP, previous dilatation, obstetric tears), iatrogenic (repeated evacuations), and DES exposure in utero. Diagnosis is clinical (a history of painless mid-trimester loss) and increasingly ultrasound-based (a cervical length under 25 mm). Management is cerclage — a suture placed around the cervix to keep it closed. Three flavours: ^[17]

^[17]

• History-indicated cerclage at 12 to 14 weeks for women with 3 or more previous second-trimester losses or preterm births.
• Ultrasound-indicated cerclage (rescue) when serial scans show a short cervix under 25 mm before 24 weeks.
• Transabdominal cerclage for women in whom a vaginal suture has failed or is not anatomically possible, placed before conception or in early pregnancy. ^[17]

^[17]

Cerclage is contraindicated in active infection, active labour, ruptured membranes, or heavy bleeding. The Cervical Insufficiency topic covers this in depth. ^[17]

^[17]

Molar pregnancy (gestational trophoblastic disease)

A must-not-miss mimic and a true neoplastic process. Molar pregnancy is a form of gestational trophoblastic disease caused by abnormal fertilisation. It can mimic miscarriage because it presents with bleeding and is diagnosed on ultrasound in early pregnancy.^[17]

Genetics and classification

• Complete mole: Usually 46,XX or 46,XY with all paternal chromosomes (diandric diploidy). There is no fetal tissue. Persistent trophoblastic disease can follow a complete mole — send all tissue for histology and follow serial hCG.
• Partial mole: Usually triploid (69 chromosomes) with two paternal and one maternal set. A fetus or fetal parts may be present, often with growth restriction and congenital anomalies. The risk of persistent trophoblastic disease is lower than after a complete mole. ^[17]

^[17]

Presentation and diagnosis

The classic presentation is heavy first-trimester bleeding with passage of vesicles (grape-like tissue), a uterus large for dates, and very high hCG. Women may have severe hyperemesis, early pre-eclampsia, or biochemical thyrotoxicosis because hCG has weak thyroid-stimulating activity. On ultrasound, a complete mole shows a heterogeneous intrauterine mass with multiple small cystic spaces classically described as a "snowstorm" or "bunch of grapes". A partial mole may show focal cystic spaces in an enlarged placenta alongside a malformed fetus.^[17]

Management

• Suction evacuation is the treatment of choice. Give syntocinon/oxytocin during or after the procedure to reduce bleeding and uterine atony.
• Because the uterus is large and soft and trophoblast is vascular, there is a higher risk of perforation and heavy bleeding; evacuation should be performed by an experienced operator and cross-matched blood should be available.
• Send all tissue for histology; the diagnosis of molar pregnancy changes follow-up completely. ^[17]

^[17]

Follow-up

After evacuation, serial serum hCG is mandatory: ^[17]

^[17]

• Weekly until hCG is negative on three consecutive occasions.
• Then monthly for six months for a complete mole (and often for a partial mole according to local protocol).
• Reliable contraception is essential during follow-up so that a new pregnancy does not confound hCG interpretation. ^[17]

^[17]

A rise or plateau in hCG indicates persistent trophoblastic disease and requires referral to a trophoblastic disease centre for staging and treatment, usually with single-agent methotrexate. Choriocarcinoma is rare but curable when treated early. ^[17]

^[17]

Anembryonic gestation (blighted ovum)

A gestational sac with a yolk sac but no embryo — the commonest form of missed miscarriage. It usually reflects an early lethal chromosomal error. Managed as a missed miscarriage with the three options above. ^[17]

^[17]

Recurrent pregnancy loss

See the dedicated workup and treatment sections above. The take-home message for exams: APS is the commonest treatable cause and warrants aspirin plus LMWH; everything else is supportive or cause-specific. ^[17]

^[17]

Complications & Pitfalls

Miscarriage is usually uncomplicated, but several serious outcomes must be anticipated and prevented. ^[9]

^[9]

Haemorrhage and anaemia

Heavy bleeding is most common in incomplete miscarriage when retained tissue prevents the uterus from contracting and the cervix from closing. The key clinical error is to rely on the reported number of pads rather than on haemodynamic signs. Tachycardia and postural dizziness are early warnings; hypotension is late. Resuscitation with crystalloid, cross-matched blood, and urgent evacuation is required for uncontrolled bleeding. After a significant bleed, check the full blood count and start oral iron if the woman is anaemic. ^[9]

^[9]

Infection and sepsis

Retained products of conception are a nidus for infection, particularly after unsafe termination or incomplete evacuation. Organisms are usually mixed aerobic and anaerobic, including Escherichia coli, Streptococcus, Staphylococcus, and gram-negative bacilli. Sepsis can progress rapidly from pyrexia and tachycardia to shock, ARDS, and DIC. The principle is antibiotics plus source control: give broad-spectrum IV antibiotics promptly and evacuate the uterus. Delaying evacuation to obtain imaging is unsafe once the diagnosis is clear. ^[10]

^[10]

Retained products of conception

On follow-up, a thickened or heterogeneous endometrium with ongoing bleeding suggests retained products. The options are expectant, medical misoprostol, or repeat suction evacuation. The choice depends on symptoms, size of retained tissue, and the woman's preference. Persistent retained products can cause chronic bleeding, anaemia, or infection. ^[9]

^[9]

Asherman syndrome

Over-vigorous or repeated curettage can damage the basalis layer of the endometrium, leading to intrauterine adhesions and Asherman syndrome. The woman presents with secondary amenorrhoea, reduced menstrual flow, infertility, or recurrent miscarriage. The risk is reduced by using suction rather than sharp curettage, gentle technique, and cervical priming. Established adhesions are treated by hysteroscopic adhesiolysis, sometimes followed by an intrauterine device or balloon to prevent re-adhesion and oestrogen to promote endometrial regrowth. ^[9]

^[9]

Cervical trauma and uterine perforation

Uterine perforation is an uncommon complication of surgical evacuation. Risk factors include an inexperienced operator, an unfavourable or undilated cervix, and retroverted uterus. Perforation may be suspected when the instrument passes beyond the expected uterine cavity, or when there is unexpected pain, bleeding, or injury to adjacent bowel or bladder. Small perforations in stable patients can be managed expectantly with antibiotics and observation; larger perforations, bleeding, or organ injury need laparoscopic or laparotomic repair. Cervical priming reduces cervical tearing. ^[9]

^[9]

Rh sensitisation

Sensitisation can cause fetal morbidity or mortality in following pregnancies. Cochrane found insufficient randomised evidence (one trial, 48 women, 300 microgram IM) to generalise anti-D after miscarriage. NICE NG126 (2026) does not offer anti-D up to 11+6 weeks; offer at least 250 IU only at 12+0 to 12+6 for medical or surgical management, and consider it for threatened miscarriage with heavy or recurrent bleeding at that gestation.^[22][15]

Psychological morbidity

Grief, guilt, anxiety, depression, and post-traumatic stress are common after miscarriage. Many women blame themselves for stress, exercise, diet, or an accidental fall, despite evidence that most losses are chromosomal and non-recurrent. Every miscarriage encounter should include empathic communication, clear explanation, and follow-up counselling. Signposting to peer-support organisations and offering early review in the next pregnancy are valuable parts of care. ^[2]

^[2]

The common diagnostic trap

The classic error — and a frequent exam trap — is declaring a pregnancy non-viable on a single borderline scan. The NICE criteria exist precisely to prevent this; when in doubt, repeat the scan at least 7 days later.^[5]

Prognosis & Disposition

Most women are managed as outpatients; admission is reserved for heavy bleeding, sepsis, significant anaemia, or social or psychological need. Prognosis worsens with advancing parental age (maternal and paternal age independently increase the rate of chromosomally abnormal loss) and with an increasing number of prior losses; in recurrent loss with inherited thrombophilia, ALIFE2 showed a 72 percent live-birth rate even without heparin. A safety-net of easy re-presentation and a follow-up review closes the episode, and periconceptional care (daily folic acid, optimisation of chronic disease, smoking cessation) sets up the next pregnancy. ^[20][12][21]

^[17]

Follow-up, pre-conception counselling and the next pregnancy

The care of a woman after miscarriage does not end once the bleeding stops. Structured follow-up improves psychological recovery, ensures complete evacuation, and prepares the woman for the safest possible next pregnancy. ^[17]

^[17]

Immediate follow-up

All women should have access to advice or a follow-up appointment within 2 to 3 weeks, or sooner if bleeding is heavy, pain is severe, or fever develops. For women managed expectantly or medically, a follow-up transvaginal ultrasound or serum beta-hCG confirms complete evacuation. A persistent thickened endometrium with ongoing bleeding suggests retained products and may need repeat medical or surgical management. Any tissue passed or evacuated should be sent for histology, and in recurrent loss or suspected molar pregnancy the products should be considered for karyotyping by array comparative genomic hybridisation or QF-PCR.^[9]

Pre-conception advice

Before the next pregnancy, review modifiable risks and chronic disease: ^[17]

^[17]

• Start daily folic acid 0.4 to 0.8 mg (400 to 800 micrograms) in the periconceptional period — USPSTF A recommendation for women planning or capable of pregnancy; most women cannot achieve the recommended intake from diet alone.^[21]
• Optimise glycaemic control, thyroid function, and blood pressure — endocrine disease is a recognised, treatable factor in recurrent loss.^[17]
• Stop smoking and reduce alcohol; aim for a healthy BMI.
• Review medications with the prescribing team before conception; coordinate anticoagulation decisions with haematology — LMWH showed no live-birth benefit in inherited thrombophilia.^[12]

Supportive care in the next pregnancy

For women with recurrent or unexplained loss, the next pregnancy is often an anxious time — structured psychological support and early reassurance are core components of care after loss.^[2] For women with APS, treat with aspirin plus heparin, the regimen international guidelines agree on.^[14] For women with bleeding in early pregnancy, the PRISM trial found vaginal progesterone 400 mg twice daily to 16 weeks did not significantly increase live births overall, and a Cochrane review concludes progestogen has little to no effect in unexplained recurrent miscarriage — offer it only within a shared decision-making framework.^[11][16]

Psychological support

Many women need more than a clinical review. Grief, anxiety, and guilt are common, and a significant minority develop depression or post-traumatic stress. Offer empathic listening, clear explanations of why the loss occurred, and information about support organisations. A follow-up appointment specifically to discuss grief and future fertility is often appreciated. Partners also grieve and should be included when appropriate. ^[17]

^[17]

When to refer

Referral to a dedicated early pregnancy assessment unit or recurrent miscarriage clinic is appropriate for women with heavy or unusual bleeding, suspected ectopic or molar pregnancy, recurrent loss, or significant psychological distress. In RPL clinics, a multidisciplinary team of obstetricians, haematologists, endocrinologists, and counsellors can deliver coordinated care. Women with two consecutive second-trimester losses, or a second-trimester loss with a suspicious history of cervical insufficiency, should also be referred for consideration of cervical cerclage. Early referral and a planned pregnancy package improve outcomes and reduce anxiety. ^[17]

^[17]

Special Populations

• Recurrent pregnancy loss — RCOG Green-top 17: three or more consecutive pregnancies, 1 percent of couples. International guidelines do not agree on the definition. APS is the most important treatable cause.^[23][14]
• Advanced maternal age — counsel on age-related risk: both maternal and paternal age independently increase the rate of chromosomally abnormal pregnancy loss.^[20]
• After IVF — greater emotional investment; structured psychological support is a core part of care after loss.^[2]
• Rh-negative women — follow NICE NG126 2026: do not offer anti-D up to 11+6 weeks; offer at least 250 IU at 12+0 to 12+6 if medical or surgical management.^[22]
• Women with recurrent miscarriage and inherited thrombophilia — ALIFE2 found no live-birth benefit from LMWH and advises against both treatment and screening; coordinate antenatal anticoagulation decisions with haematology.^[12]
• Women with diabetes and other endocrine disease — optimise control pre-conception; endocrine factors are an established, treatable category in recurrent-loss management.^[17]

Evidence, Guidelines & Regional Differences

^{[22] [23] [5] [4] [14] [24] [10] [16]}

Landmark trials

• MifeMiso trial (Chu et al., Lancet 2020, PMID 32853559): a multicentre, double-blind, placebo-controlled randomised trial of 711 women with missed miscarriage in 28 UK hospitals. All received misoprostol 800 microgram two days after mifepristone 200 mg or placebo: fewer women in the mifepristone group failed to pass the gestational sac within 7 days (17 percent vs 24 percent; RR 0.73) and fewer needed surgical intervention (17 percent vs 25 percent).^[8]
• PRISM trial (Coomarasamy et al., N Engl J Med 2019, PMID 31067371): 4,153 women with bleeding in early pregnancy randomised to vaginal progesterone 400 mg twice daily or placebo through 16 weeks. Live births after at least 34 weeks were 75 percent vs 72 percent (RR 1.03, P=0.08) — progesterone did not significantly increase live births.^[11]
• ALIFE2 trial (Quenby et al., Lancet 2023, PMID 37271152): 326 women with two or more pregnancy losses and confirmed inherited thrombophilia randomised to LMWH or standard care; livebirths 72 percent vs 71 percent (aOR 1.08). The authors advise against LMWH and against inherited-thrombophilia screening in recurrent pregnancy loss; aspirin plus LMWH remains standard only in antiphospholipid syndrome.^[12]
• APS classification (Sydney international consensus statement, Miyakis et al.): the revised Sapporo classification criteria for definite APS, on which the laboratory diagnosis (persistent lupus anticoagulant, anticardiolipin, anti-beta-2-glycoprotein-I antibodies) and the aspirin-plus-heparin treatment strategy rest.^[18][14]

Exam Pearls

The one-liners examiners reward: ^[17]

^[17]

• "Miscarriage equals spontaneous loss before viability (UK: until 24 weeks); 15.3 percent of recognised pregnancies; chromosomal abnormality of the conceptus in about half to two-thirds."^[23][24][20]
• "The cervical os decides the type: closed and viable equals threatened; open equals inevitable or incomplete; closed and retained equals missed; infection equals septic."^[10]
• "NICE: CRL 7.0 mm or MSD 25.0 mm is not enough on its own — second opinion and/or rescan at least 7 days later."^[22]
• "Empty uterus plus a positive test equals PUL — serial hCG plus rescan. A single hCG, including discriminatory-zone values, does not exclude ectopic."^[7]
• "RCOG recurrent miscarriage equals 3 or more consecutive losses; the treatable cause is APS: aspirin plus heparin. Guidelines do not agree on the numeric definition."^[23][14]
• "NICE 2026: do not offer anti-D up to 11+6 weeks; offer at least 250 IU at 12+0 to 12+6 if medical or surgical management."^[22]
• "In inherited thrombophilia with recurrent loss, LMWH does not improve live birth — and screening is not advised (ALIFE2)."^[12]
• "Anembryonic sac with no embryo equals blighted ovum."
• "Septic miscarriage: prompt evacuation plus IV antibiotics plus IV fluids — never forget retained products and an unsafe-procedure history."^[10]
• "Cervical insufficiency: painless second-trimester dilation with bulging membranes — consider cerclage if viable."^[17]
• "Complete mole has no fetus; partial mole is triploid with a fetus."
• "Molar pregnancy follow-up is serial hCG to detect persistent trophoblastic disease."^[17]

Exam application bank (NEET-PG / INICET)

One-line answer

Miscarriage is the spontaneous loss of a pregnancy before viability (UK: until 24 weeks of gestation). Pooled risk is 15.3 percent of recognised pregnancies (~23 million losses per year worldwide). Types hinge on the cervical os and ultrasound viability. Chromosomal abnormality of the conceptus is found in about half of products of conception (67.8 percent after haplarithmisis). NICE NG126: expectant first-line; missed miscarriage mifepristone 200 mg then misoprostol 800 micrograms 48 hours later; do not offer anti-D up to 11+6 weeks. RCOG recurrent miscarriage is three or more consecutive losses; APS is the key treatable cause (aspirin plus heparin).^[22][23][24]

Worked stems (answer without another resource)

Stem 1 — Classic presentation. Map symptoms to mechanism; name the first investigation and first treatment step with dose/route if drug therapy is standard. ^[17]

Stem 2 — Unstable / complicated. List red flags that force immediate resuscitation, theatre, ICU, antidote, or reperfusion — and what you do in the first 15 minutes. ^[17]

Stem 3 — Atypical group. Elderly, pregnancy, child, or immunocompromised: how presentation and thresholds change. ^[17]

Stem 4 — Differential trap. Name the three closest mimics and one discriminator for each. ^[17]

Stem 5 — Disposition. Who goes home with safety-netting, who is admitted, who needs HDU/ICU/theatre, and what follow-up is mandatory. ^[17]

Rapid viva checklist

1. Definition + classification
2. Pathophysiology chain
3. Bedside signs / criteria
4. Score with exact components (if any)
5. Emergency bundle
6. Definitive therapy with doses
7. Complications of disease and of treatment
8. Special populations
9. Guideline/trial name if classic
10. Three exam traps

Coverage self-check

If you cannot answer any stem above from this page alone, re-read the matching section — the page is intended to be self-sufficient for final-prof and NEET-PG/INICET questions on Miscarriage & Recurrent Pregnancy Loss.

^{[17] [17]}

References27ShowHide

1. [1]Zimowski JG, Massalska D, Pawelec M, et al. First-trimester spontaneous pregnancy loss - molecular analysis using multiplex ligation-dependent probe amplification Clin Genet, 2016.PMID 26748861
2. [2]Tetruashvili N, Domar A, Bashiri A. Prevention of Pregnancy Loss: Combining Progestogen Treatment and Psychological Support J Clin Med, 2023.PMID 36902614
3. [3]Tóth E, Posta M, Györffy D, et al. Novel proteomics biomarkers of recurrent pregnancy loss reflect the dysregulation of immune interactions at the maternal-fetal interface Front Immunol, 2025.PMID 40948775
4. [4]Hennessy M, Dennehy R, Meaney S, et al. A protocol for a systematic review of clinical practice guidelines for recurrent miscarriage HRB Open Res, 2020.PMID 33005862
5. [5]Hu M, Poder L, Filly RA, et al. Impact of new society of radiologists in ultrasound early first-trimester diagnostic criteria for nonviable pregnancy J Ultrasound Med, 2014.PMID 25154939
6. [6]Infante F, Casikar I, Menakaya U, et al. Rationalising the change in defining non-viability in the first trimester Australas J Ultrasound Med, 2013.PMID 28191184
7. [7]Condous G, Kirk E, Lu C, et al. Diagnostic accuracy of varying discriminatory zones for the prediction of ectopic pregnancy in women with a pregnancy of unknown location Ultrasound Obstet Gynecol, 2005.PMID 16308901
8. [8]Chu JJ, Devall AJ, Beeson LE, et al. Mifepristone and misoprostol versus misoprostol alone for the management of missed miscarriage (MifeMiso): a randomised, double-blind, placebo-controlled trial Lancet, 2020.PMID 32853559
9. [9]Trinder J, Brocklehurst P, Porter R, et al. Management of miscarriage: expectant, medical, or surgical? Results of randomised controlled trial (miscarriage treatment (MIST) trial) BMJ, 2006.PMID 16707509
10. [10]Banwarth-Kuhn B, McQuade M, Krashin JW. Vaginal Bleeding Before 20 Weeks Gestation Obstet Gynecol Clin North Am, 2023.PMID 37500211
11. [11]Coomarasamy A, Devall AJ, Cheed V, et al. A Randomized Trial of Progesterone in Women with Bleeding in Early Pregnancy N Engl J Med, 2019.PMID 31067371
12. [12]Quenby S, Booth K, Hiller L, et al. Heparin for women with recurrent miscarriage and inherited thrombophilia (ALIFE2): an international open-label, randomised controlled trial Lancet, 2023.PMID 37271152
13. [13]Townsend J, Attala R. Re-evaluating low-molecular-weight heparin use in recurrent missed miscarriage: current evidence and future directions J Obstet Gynaecol, 2026.PMID 42495882
14. [14]Youssef A, Vermeulen N, Lashley EELO, et al. Comparison and appraisal of (inter)national recurrent pregnancy loss guidelines Reprod Biomed Online, 2019.PMID 31182358
15. [15]Karanth L, Jaafar SH, Kanagasabai S, et al. Anti-D administration after spontaneous miscarriage for preventing Rhesus alloimmunisation Cochrane Database Syst Rev, 2013.PMID 23543581
16. [16]Haas DM, Bofill Rodriguez M, Hathaway TJ, et al. Progestogen for preventing miscarriage in women with recurrent miscarriage of unclear etiology Cochrane Database Syst Rev, 2025.PMID 40497447
17. [17]Deng T, Liao X, Zhu S. Recent Advances in Treatment of Recurrent Spontaneous Abortion Obstet Gynecol Surv, 2022.PMID 35672876
18. [18]Miyakis S, Lockshin MD, Atsumi T, et al. International consensus statement on an update of the classification criteria for definite antiphospholipid syndrome (APS) J Thromb Haemost, 2006.PMID 16420554
19. [19]Schreiber CA, Sonalkar S Tubal Ectopic Pregnancy N Engl J Med, 2025.PMID 39970398
20. [20]Essers R, Lebedev IN, Kurg A, et al. Prevalence of chromosomal alterations in first-trimester spontaneous pregnancy loss Nat Med, 2023.PMID 37996709
21. [21]Bibbins-Domingo K, Grossman DC, Curry SJ, et al. Folic Acid Supplementation for the Prevention of Neural Tube Defects: US Preventive Services Task Force Recommendation Statement JAMA, 2017.PMID 28097362
22. [22]National Institute for Health and Care Excellence Ectopic pregnancy and miscarriage: diagnosis and initial management NICE guideline NG126, 2026.Source
23. [23]Royal College of Obstetricians and Gynaecologists The Investigation and Treatment of Couples with Recurrent First-trimester and Second-trimester Miscarriage Green-top Guideline No. 17, 2011.Source
24. [24]Quenby S, Gallos ID, Dhillon-Smith RK, et al. Miscarriage matters: the epidemiological, physical, psychological, and economic costs of early pregnancy loss Lancet, 2021.PMID 33915094
25. [25]Nybo Andersen AM, Wohlfahrt J, Christens P, et al. Maternal age and fetal loss: population based register linkage study BMJ, 2000.PMID 10864550
26. [26]Bender Atik R, Christiansen OB, Elson J, et al. ESHRE guideline: recurrent pregnancy loss: an update in 2022 Hum Reprod Open, 2023.PMID 36873081
27. [27]Bender Atik R, Christiansen OB, Elson J, et al. ESHRE guideline: recurrent pregnancy loss Hum Reprod Open, 2018.PMID 31486805