Study Finds No Link Between Paternal Use of Diabetes Medication and Birth Defects in Babies

New Delhi: A recent large-scale study has provided reassurance to men with type 2 diabetes who are planning to start a family, suggesting that the use of the diabetes drug metformin does not increase the risk of birth defects in their children. The findings, published on Thursday in The BMJ, analyzed over 3 million pregnancies and indicated that metformin remains a safe option for managing blood sugar levels in men planning to have children.

The study, led by researchers from Taiwan and Norway, counters previous concerns raised by a Danish study, which suggested a potential link between paternal metformin use and an increased risk of congenital malformations, particularly genital defects in male infants. Metformin is a widely prescribed medication for treating type 2 diabetes, including in men of reproductive age, and these new findings aim to clarify its safety profile in this context.

To conduct the research, the team utilized national birth registries and prescription databases from both Norway and Taiwan, focusing on pregnancies where paternal metformin use occurred during the critical period of sperm development, which spans approximately three months before conception. They examined 619,389 babies born in Norway between 2010 and 2021, and 2,563,812 babies born in Taiwan between 2004 and 2018. Among these, 2,075 babies in Norway (0.3%) and 15,276 babies in Taiwan (0.6%) had fathers who used metformin during the sperm development period.

After adjusting for factors such as the father's age and related health conditions, the researchers found no evidence of an increased risk of congenital malformations among babies whose fathers had used metformin during this period. This held true for overall congenital defects as well as specific organ-related malformations, including genital abnormalities.

“These results provide reassurance and can assist clinicians in making informed treatment decisions when selecting metformin for managing type 2 diabetes among men planning a family,” stated the research team from National Taiwan University and the University of Oslo.

However, the authors did emphasize that the study was observational, meaning it could not establish a direct cause-and-effect relationship. They also noted some limitations, including potential inaccuracies in the diagnostic data and the possibility of misclassification in drug usage records.

Despite these limitations, the findings offer significant reassurance to men with type 2 diabetes, confirming that metformin does not pose a heightened risk of birth defects, providing clearer guidance for clinicians managing patients planning to conceive.