994: Metformin and type 2 diabetes: could metformin exposure prevent preeclampsia?

Abstract

Metformin has been found to have a role in promoting vascular remodeling and angiogenesis, which may reduce the risk of developing preeclampsia. Prior studies have shown a decrease in hypertensive disorders of pregnancy (HTN) in patients with gestational diabetes taking metformin. We hypothesize metformin exposure decreases the risk of developing HTN in patients with type 2 diabetes. Retrospective cohort study from 2009-2019 of singleton pregnancies complicated by type 2 diabetes. We compared patients who received metformin throughout pregnancy to those with no metformin exposure. The primary outcome was a hypertension composite defined as gestational hypertension, preeclampsia with or without severe features, or HELLP syndrome. Individual hypertensive outcomes and neonatal outcomes were secondarily evaluated. Logistic regression was used adjust for confounding variables. Of 41,472 deliveries, 254 pregnancies were included. Women receiving metformin had a higher pre-pregnancy BMI and were more likely to have chronic hypertension and prior hypertensive disorder of pregnancy than women who were not exposed to metformin. 91% of women in the metformin group were taking it at conception or received it in the first trimester. Women exposed to metformin were significantly less likely to develop the hypertension composite compared to non-exposed women (22.7% vs 33.1% (aOR 0.53, 95%CI 0.29-0.96)). The incidence of preeclampsia with severe features was also significantly reduced in those who received metformin compared to those who did not (12.1% vs 20.7%, (aOR 0.38, 95% CI 0.18-0.81)) (Table). There were no differences in preterm birth prior to 34 or 37 weeks, fetal growth restriction, or birth weight between the study groups. Metformin exposure was associated with a decreased risk of the hypertension composite and preeclampsia with severe features in patients with pregestational type 2 diabetes. These data suggest there may be benefit to metformin administration beyond glycemic control in this patient population.