Objectives: To test the hypothesis that metformin during lactation versus formula feeding would have no adverse effects on infants' growth, motor-social development, or intercurrent illness.
Study design: Growth, motor-social development, and illness requiring a pediatrician visit were assessed in 61 nursing infants (21 male, 40 female) and 50 formula-fed infants (19 male, 31 female) born to 92 mothers with polycystic ovary syndrome (PCOS) taking a median of 2.55 g metformin per day throughout pregnancy and lactation.
Results: Within sex, at 3 and 6 months of age, weight, height, and motor-social development did not differ (p > or = .06) between breast- and formula-fed infants. No infants had retardation of growth, motor, or social development. Intercurrent illnesses did not differ.
Conclusions: Metformin during lactation appears to be safe and effective in the first 6 months of infancy.