Assessing causality in associations between maternal adiposity and obstetric and perinatal outcomes: A Mendelian randomization study

Observational studies consistently suggest that maternal obesity is related to a number of adverse perinatal outcomes. However, which of these are causal or due to confounding is unclear. We aimed to carry out Mendelian randomization (MR), which uses genetic variants robustly associated with the exposure of interest as instrumental variables (IV), to determine the causal effect of maternal BMI on clinically important obstetric and perinatal outcomes.