A 29-year-old woman at 27 weeks is diagnosed with gestational diabetes mellitus. She refuses insulin injections. Dietary control fails and she needs pharmacotherapy. Which oral agent is considered acceptable in pregnancy because it does not cross the placenta significantly?
- A Glibenclamide ✓
- B Metformin
- C Glimepiride
- D Pioglitazone
Correct answer: A. Glibenclamide
Explanation
Glibenclamide has negligible placental transfer because it is highly protein bound and actively effluxed by placental transporters, making it an accepted alternative when insulin is refused. Metformin does cross the placenta freely, reaching fetal levels comparable to maternal levels, though it remains widely used under DIPSI and FIGO guidance. Glimepiride and other second generation sulfonylureas cross the placenta and risk fetal hypoglycaemia, and pioglitazone is contraindicated in pregnancy.
Reference: Williams Obstetrics, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.