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

BJOG. 2015 Jun;122(7):994-1000. doi: 10.1111/1471-0528.12964. Epub 2014 Jul 16.


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.

Keywords: Gestational diabetes mellitus; metformin; offspring.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Body Height / physiology*
  • Body Weight / physiology*
  • Child Development / physiology*
  • Diabetes, Gestational / drug therapy*
  • Female
  • Follow-Up Studies
  • Humans
  • Hypoglycemic Agents / therapeutic use*
  • Infant
  • Insulin / therapeutic use
  • Male
  • Metformin / therapeutic use
  • Pregnancy
  • Randomized Controlled Trials as Topic
  • Surveys and Questionnaires


  • Hypoglycemic Agents
  • Insulin
  • Metformin