Genetically predicted body mass index and maternal outcomes of pregnancy: A two-sample Mendelian randomisation study.

Higher genetically predicted BMI is associated with marked increase in risk of pre-eclampsia, gestational diabetes and polyhydramnios. The relation between genetically predicted BMI and premature rupture of membranes and postpartum depression should be assessed in further studies. Our study supports efforts to target BMI as a cardinal risk factor for maternal morbidity in pregnancy.