PI4 - A Trial Assessing Metformin to Prolong Gestation in Preterm Preeclampsia

Preeclampsia is globally responsible for 60,000 maternal deaths per year, and far greater numbers of fetal losses. Preterm preeclampsia is a severe variant with the highest rates of neonatal morbidity and mortality due to iatrogenic preterm birth (clinicians are forced to deliver the baby preterm for maternal or fetal health reasons). There is preclinical evidence suggesting metformin, a drug commonly used to treat diabetes in and outside pregnancy, may be able to counter the pathophysiology of preeclampsia, raising the possibility that it could be used to treat the condition. Previous research from the Preeclampsia Intervention 2 trial (PI2) show that metformin was able to delay delivery in early preterm preeclampsia. Metformin extended release (ER) was associated with a median 7.6-day prolongation of pregnancy (geometric mean ratio (GMR) 1.39 (95% CI 0.99 to 1.96) P=0.057).Trends towards increased birthweight (mean difference 110gm (95%CI -80 to 300), a decreased length of stay at the neonatal intensive care unit (median difference 5.0 days less; GMR 0.86, 95% CI 0.62 to 1.2) and a shorter period of admission in any neonatal ward (median difference 12.0 days less; GMR 0.82, 95% CI 0.57 to 1.18) in the metformin ER group were found. Importantly, while gastrointestinal side effects were common, no serious adverse events related to trial medications were observed. The PI 2 trial has shown that metformin may be a disease modifying treatment for preterm preeclampsia. The trial is being repeated in a larger scale in the PI3 trial in South Africa to also assess neonatal outcomes. In the Nordic countries, the demographics of the population are different and expectant management of preeclampsia allows for the women to reach 37 weeks of gestation as opposed to 34 weeks of gestation in the PI2 trial. This trial aims to investigate if metformin can prolong gestation, lower neonatal length of stay and increase birthweight in a Nordic setting. Follow up of mothers and children will be carried out two years post partum.