Anna P. Kenyon, MBChB, MD; Andrew H. Shennan, MBBS, MD
In gestational diabetes, is metformin (plus insulin as needed) as effective as insulin for preventing perinatal complications?
Randomized controlled trial (Metformin in Gestational Diabetes [MiG] Trial).
6 to 8 weeks postpartum.
10 obstetric hospitals in New Zealand and Australia.
751 women 18 to 45 years of age (mean age 33 y) who were 20- to 33-weeks pregnant with a single healthy fetus and had gestational diabetes requiring medical treatment (fasting blood glucose > 5.4 mmol/L [97.2 mg/dL] or 2-hour postprandial blood glucose > 6.7 mmol/L [120.6 mg/dL] on > 1 occasion after lifestyle intervention). Exclusion criteria included prepregnancy diabetes, hypertensive disorders, and ruptured membranes.
Metformin, 500 mg once or twice daily, increased to a maximum of 2500 mg/d, with insulin added as needed (n = 373) or insulin administered according to each center's standard practice (n = 378). Target levels were < 5.5 mmol/L (99 mg/dL) for fasting and < 7.0 mmol/L (126 mg/dL) for 2-h postprandial blood glucose (or less).
Composite neonatal outcome (hypoglycemia, respiratory distress, need for phototherapy, birth trauma, 5-min Apgar score < 7, or preterm birth) and maternal hypertensive complications and weight gain. The study had 80% power to detect an absolute difference of 10% in the primary composite outcome with an alpha level of 0.05.
98% (intention-to-treat analysis).
Groups did not differ for the composite neonatal outcome or any of its components, except for severe hypoglycemia and preterm birth (Table). Groups did not differ for gestational hypertension or preeclampsia. Women in the metformin group gained less weight (0.4 vs 2.0 kg, P < 0.001).
In gestational diabetes, metformin (plus insulin as needed) was as effective as insulin for preventing perinatal complications.
Metformin (alone or with insulin) vs insulin for gestational diabetes‡
‡Abbreviations defined in Glossary. RRR, RRI, NNT, NNH, and CI calculated from data in article.
§Hypoglycemia, respiratory distress, need for phototherapy, birth trauma, 5-min Apgar score < 7, or preterm birth.
Kenyon AP, Shennan AH. Metformin (alone or with insulin) was as effective as insulin for preventing perinatal complications in gestational diabetes. Ann Intern Med. ;149:JC2–7. doi: 10.7326/0003-4819-149-4-200808190-02007
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Published: Ann Intern Med. 2008;149(4):JC2-7.
Cardiology, Coronary Risk Factors, Diabetes, Endocrine and Metabolism.
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