Pregnancy outcomes in a cohort of women with a preconception body mass index >50 kg/m².

We describe characteristics and risk factors regarding pregnancy outcome in women with a preconception body mass index (BMI) >50 kg/m² compared with women with BMI ≤50 kg/m² in a retrospective population cohort study in singleton pregnancies from the Danish Medical Birth Registry. Results were analyzed as relative risks by a two-proportion z-test. Women with preconception BMI >50 kg/m² smoked, developed gestational diabetes and pre-eclampsia, and needed induction of labor more frequently than mothers with BMI ≤50 kg/m². Examination of the case records showed that many attempted vaginal delivery without epidural analgesia, 21% needed an emergency cesarean section (compared with 12% among women with BMI ≤50 kg/m²), and 25% underwent general anesthesia in this context. Many neonates were macrosomic and 34% needed neonatal intensive care and early feeding compared with 6% of neonates from women with BMI ≤50 kg/m². Women with an extremely high preconception BMI develop more pregnancy complications and their neonates appear affected by this as well.