Body mass index at 11–13 weeks’ gestation and pregnancy complications in a Southern Chinese population: a retrospective cohort study

Objective: To assess the association between body mass index (BMI) and adverse pregnancy outcomes.Materials and methods: A multicentre retrospective cohort study was conducted in three hospitals in Hong Kong including 67,248 women with singleton pregnancy at 11–13 weeks between 2010 and 2016. The relationship between maternal BMI and (1) miscarriage or stillbirth, (2) development of preeclampsia (PE), (3) gestational hypertension (GH), (4) development of gestational diabetes mellitus (GDM), (5) spontaneous preterm delivery (sPTD)