A follow-up of a randomised study of metformin and insulin in gestational diabetes mellitus: growth and development of the children at the age of 18 months.

OBJECTIVE

To compare the growth and development of children born to mothers with gestational diabetes mellitus (GDM) requiring pharmacological treatment, and randomised to treatment with metformin or insulin.

DESIGN

Follow-up of a randomised controlled trial (RCT) comparing metformin and insulin treatment of GDM.

SETTING

Data were gathered during routine visits to child welfare clinics at the ages of 6, 12, and 18 months, including weight and height measurements, and assessment of motor, social, and linguistic development.

SAMPLE

The children of mothers with GDM randomised to metformin (n = 47) or insulin (n = 50) treatment during pregnancy.

METHODS

Data were collected from the structured questionnaire filled in at the child welfare clinics.

MAIN OUTCOME MEASURES

The growth and development of the children until the age of 18 months.

RESULTS

Children exposed to metformin were significantly heavier (10.47 versus 9.85 kg, 95% CI 0.04-1.20) at the age of 12 months and taller and heavier (83.9 vs 82.2 cm, 95% CI 0.23-3.03, 12.05 vs 11.32 kg, 95% CI 0.04-1.43) at the age of 18 months. The mean ponderal index (PI) did not differ significantly. The motor, social, or linguistic development evaluated at the age of 18 months did not differ between the groups.

CONCLUSIONS

Children prenatally exposed to metformin were heavier at the 12 months measurements and taller and heavier at the 18 months measurements than those exposed to insulin, but their body composition defined by PI did not differ. Over the short term, metformin does not seem to be harmful with regards to early motor, linguistic, or social development.