Metformin in pregnancy and its adverse long-term outcomes, BMJ study

A recent study published in BMJ Open Diabetes Research and Care, aimed to investigate if maternal pregnancy exposure to metformin is associated with increased risk of long-term and short-term adverse outcomes in the child.

Study was conducted in Finland included singleton children born 2004-2016 with maternal pregnancy exposure to metformin or insulin, 3967 participants were given metformin only , 5273 insulin only and 889 combination treatment. 

The primary outcomes were long-term offspring obesity, hypoglycemia, hyperglycemia, diabetes, hypertension, polycystic ovary syndrome, and challenges in motor social development. In a sensitivity analysis, the primary outcomes were investigated only among children with maternal gestational diabetes.

Secondary outcomes were adverse outcomes at birth. Study found that exposure to metformin or combination treatment versus insulin was not associated with neonatal mortality, hyperglycemia, or major congenital anomalies.

Study concluded that no increased long-term risk associated with pregnancy exposure to metformin (alone or in combination with insulin), compared with insulin. The increased risks of adverse outcomes at birth associated with combination treatment may reflect confounding by indication or severity.