Scientists compared the risk of malformations when prescribed insulin and metformin
The risk of birth defects did not differ in children whose mothers received metformin or insulin in the first trimester of pregnancy for type 2 diabetes. The likelihood of cardiovascular birth defects was also similar, but the risk increased with a combination of drugs.Researchers from the Norwegian Institute of Public Health, Karolinska Institute, University of Iceland, and Finnish Institute of Health and Welfare compared the risk of birth defects in children whose mothers received metformin, insulin, or both drugs simultaneously during the first trimester of pregnancy. The study was published in the journal Diabetes Care.
Birth defects were diagnosed in 147 (4.7%) of 3,145 children in the metformin-exposed group (alone or together with insulin). Also, malformations were found in 50 (5.7%) of the 878 participants who were exposed to insulin alone. Congenital malformations were found in 127 (4.4%) of the 2852 newborns whose mothers were exposed to metformin alone. In addition, congenital abnormalities were diagnosed in 20 (6.8%) of 293 children who were exposed to both drugs simultaneously.
The analysis showed no increased risk of congenital malformations with metformin exposure (hazard ratio (HR) 0.83) or with the combination of both drugs (OR = 0.98) when compared with insulin. The risk of cardiovascular malformations with metformin alone was comparable to insulin (OR = 0.92), but with a combination of drugs there was a 72% increased chance of malformations.
Data from 3.7 million newborns born to women with type 2 diabetes were analyzed. The analysis included 4,023 children whose mothers had received metformin, insulin, or both drugs simultaneously during the first trimester of pregnancy.
The authors urged caution in interpreting the results of the study, because the analysis did not take into account glycemic levels.