(676) Does Metformin Use in Pregnancy Decrease Infection Risk?: A Secondary Analysis of The MOMPOD Trial

Outside of pregnancy, metformin use has been variably associated with lower risk of infections. It is unknown whether this association is true in the pregnant population. Pregnancy is associated with an adaptive immunophenotype and thus may have more severe infections. We sought to assess if metformin use in pregnancy decreased rates of infection.

Study Design:
This is a secondary analysis from the MOMPOD randomized trial comparing the addition of metformin versus placebo to the insulin regimen of pregnant people with early gestational or pre-existing Type 2 diabetes <23 weeks’ gestation. We included those aged 18-46 who took at least one dose of study drug (metformin or placebo). The primary outcome was a composite of any infection during pregnancy or postpartum (chorioamnionitis, postpartum endometritis, mastitis, wound infections, COVID-19, pyelonephritis, pneumonia, urinary tract infection, and septic pelvic thrombophlebitis). Secondary outcomes were infection-related maternal and neonatal complications (neonatal sepsis, postpartum hemorrhage, wound complications). Categorical variables were analyzed using Pearson Chi square and Fisher exact test. 

Results:
N=808 participants were included in this analysis (n=404 on metformin and n=404 placebo). The majority (77.1%) of participants had diabetes prior to pregnancy. Of those diagnosed in early pregnancy, the majority were either diagnosed using the 2-step method (27.6%) or with an HbA1c ≥ 6.5% (28.1%). There were no significant differences in participant demographics (Table 1). Overall, no significant difference in any infections during pregnancy were observed between the metformin and placebo groups [RR: 0.94 (95% CI: 0.71, 1.24, p=0.764)]. No cases of mastitis, pyelonephritis, or septic pelvic thrombophlebitis were observed. There were also no differences in the secondary outcomes (Table 2). 

Conclusion:

Metformin use in pregnancy does not appear to decrease the rate of infections or related complications during pregnancy (neither antenatal or intrapartum) or in the postpartum period.