A 30-year-old woman with pre-gestational Type 2 diabetes mellitus on metformin 1000 mg twice daily and glargine insulin 40 units at bedtime presents at 10 weeks gestation. Fasting glucose is consistently 115-125 mg/dL. According to standard guidelines, what is the most appropriate change to her regimen at this gestation?

• A Continue metformin and adjust basal insulin to target fasting glucose below 95 mg/dL; metformin is acceptable as adjunct therapy in pregnancy ✓
• B Discontinue metformin immediately as it crosses the placenta and is associated with embryopathy
• C Continue metformin and add rapid-acting insulin analog with meals; metformin is contraindicated in the first trimester
• D Switch entirely to NPH insulin twice daily and discontinue metformin because NPH is the only insulin proven safe in the first trimester

Explanation

Metformin is acceptable in pregnancy for pre-gestational diabetes, particularly in women with insulin resistance or polycystic ovary syndrome, and is continued in many protocols alongside insulin. The target fasting glucose in pregnancy is below 95 mg/dL. Distractor C is wrong because metformin is not contraindicated in the first trimester. Distractor B is wrong because metformin is not associated with a specific embryopathy pattern. Distractor D is wrong because insulin analogs (lispro, aspart, detemir) are preferred over NPH in many modern protocols, and complete insulin replacement is not mandatory if metformin is effective.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.