December 2024
New study finds paternal metformin use not linked to neonatal congenital malformations
By Melanie Hinze
Paternal metformin use is not linked to congenital malformations in offspring, according to new research published in the BMJ.
The population based, crossnational cohort study followed on from a Danish study published in 2022 (https://pubmed.ncbi.nlm.nih.gov/35344380/) that had found that prescription metformin taken by fathers during preconception was associated with an increased risk of major congenital malformations among offspring, compared with insulin.
Dr Hannah Gordon, Obstetrics and Gynaecology Registrar at the Mercy Hospital for Women, Melbourne, and PhD candidate at the University of Melbourne, told Medicine Today that this earlier research was a cause for concern because although substantial research had found no link between maternal metformin and malformations, very little research had until then looked at fathers.
The current study included 619,389 offspring with paternal data during the period of sperm development in a Norwegian cohort from 2010 to 2021, and 2,563,812 offspring in a Taiwanese cohort from 2004 to 2018.
Paternal data on metformin use was available for 2074 (0.3%) offspring in the Norway cohort and 15,276 (0.6%) offspring in the Taiwan cohort. Among these, 5% and 3.4% of offspring had congenital malformations in the Norway and Taiwan cohorts, respectively.
When the analysis was adjusted to only fathers with type 2 diabetes mellitus, paternal metformin use during the period of sperm development was not associated with congenital malformations in either cohorts.
‘There is currently insufficient evidence to suggest that paternal metformin use increases the likelihood of neonatal congenital anomalies; however, these findings are at odds with the original Danish study and clinicians may wish to discuss these discrepancies with their patients,’ Dr Gordon said.
‘The decision to cease or continue metformin among male patients planning pregnancy should be individualised, with future research providing further guidance in this area,’ she said.
‘Metformin continues to have a very important role in managing diabetes and metabolic syndrome, and the available research does not provide sufficient evidence to justify metformin cessation in patients where its use is clinically necessary,’ Dr Gordon added.