Gestational Diabetes Mellitus — SAQ 2

Stem

This paper's regional pathways are reader-verifiable at NICE NG3 and the BAPM 2024 neonatal framework.^[4]

A 29-year-old woman with insulin-treated GDM presents in established labour at 37+0 weeks, 48 hours after her first antenatal betamethasone dose at 36+5 weeks for threatened preterm birth; the steroid course was completed 24 hours ago. Her latest estimated fetal weight is 3.1 kg. Capillary glucose is 9.2 mmol/L. The maternity unit follows the NICE intrapartum pathway and, because the infant is now full term, the BAPM 2024 neonatal framework.^[2][4]

Questions and model answer

a) Why may glucose be elevated, and what are the first actions? (2 marks)

• 1 mark: Late-pregnancy insulin resistance is increased by placental/maternal signals, and antenatal corticosteroids can add transient hyperglycaemia; review the recent glucose trend and insulin exposure rather than assuming non-adherence.^[1][2]
• 1 mark: Because she is insulin-treated and received antenatal steroids, implement protocolised additional insulin with close glucose monitoring as required by NICE NG3. Confirm the capillary result only if clinically discordant, assess ketones/illness when indicated, alert the obstetric-diabetes team and start the intrapartum plan without delaying labour/fetal assessment.^[2]

b) Outline NICE intrapartum glucose management. (3 marks)

• 1 mark: Check capillary glucose hourly during labour and birth and aim for 4 to 7 mmol/L, following NICE NG3.
• 1 mark: Her glucose is already 9.2 mmol/L, outside range: start the maternity protocol's intravenous dextrose and insulin infusion now; repeat first only if the result is clinically discordant. Do not wait for another out-of-range value. This is the NICE NG3 trigger.
• 1 mark: Avoid inventing a universal 50-unit bag, dextrose rate or sliding scale. Document each result, treatment change and hypoglycaemia response; coordinate anaesthetic and neonatal teams because recent steroids, maternal diabetes and imminent early-term birth require coordinated care.^[2]

c) Explain the newborn hypoglycaemia mechanism and prevention. (2 marks)

• 1 mark: Maternal glucose crosses the placenta while maternal insulin ordinarily does not. Fetal hyperglycaemia stimulates fetal insulin; after cord clamping the glucose supply stops while fetal insulin persists.^[1]
• 1 mark: NICE NG3 supports skin-to-skin care, feeding as soon as possible and within 30 minutes, then every 2 to 3 hours, and routine glucose testing at 2 to 4 hours. The BAPM 2024 framework separately specifies testing before the second feed (2 to 4 hours), with further checks under the local pathway.^[4]

d) The infant is well but the local neonatal threshold is breached. Give the gel calculation and escalation boundary. (2 marks)

• 1 mark: The BAPM 2024 neonatal framework specifies 40% dextrose gel 200 mg/kg, approximately 0.5 mL/kg buccally because the gel contains about 400 mg/mL; support a feed and recheck at the protocol-defined interval.^[4]
• 1 mark: Symptoms, recurrent/persistent low glucose or inability to feed require immediate neonatal review and protocolised IV glucose under the BAPM/local pathway. Do not quote one universal IV bolus volume without the neonatal guideline.^[4]

e) What information must accompany mother and infant at handover? (1 mark)

• 0.5 mark: Maternal GDM treatment, last insulin, steroid timing, protocolised additional insulin, intrapartum glucose trend and any dextrose/insulin infusion.^[2]
• 0.5 mark: Gestation, feeding time, newborn glucose values, gel dose/time and the explicit threshold for neonatal escalation under the BAPM/local pathway.^[4]

Reproducible total: 2 + 3 + 2 + 2 + 1 = 10 marks.^[2]

This SAQ assesses steroid-associated intrapartum and neonatal safety; it deliberately does not duplicate SAQ 1's diagnosis, antepartum pharmacotherapy, surveillance or delivery-timing marks.^[2]

References4ShowHide

1. [1]Plows JF, Stanley JL, Baker PN, Reynolds CM, Vickers MH. The Pathophysiology of Gestational Diabetes Mellitus Int J Mol Sci, 2018.PMID 30373146
2. [2]ACOG. ACOG Practice Bulletin No. 190: Gestational Diabetes Mellitus Obstet Gynecol, 2018.PMID 29370047
3. [3]ACOG. ACOG Clinical Practice Update: Screening for Gestational and Pregestational Diabetes in Pregnancy and Postpartum Obstet Gynecol, 2024.PMID 42131962
4. [4]Harris DL, Weston PJ, Signal M, Chase JG, Harding JE. Dextrose gel for neonatal hypoglycaemia (the Sugar Babies Study): a randomised, double-blind, placebo-controlled trial Lancet, 2013.PMID 24075361