Weighted probability of adverse pregnancy outcomes by gestational weight gain rate, stratified by pre-pregnancy BMI. Analysis of 104,070 singleton pregnancies in nulliparous Japanese women. Complicated delivery includes any of the following: cesarean section, forceps or vacuum delivery, obstructed labor, post-partum hemorrhage. Probability shown is estimated for women of 30 years of age, 160-cm height, and average BMI of each strata (17.9 kg/m2, 19.3 kg/m2, 21.2 kg/m2, 23.8 kg/m2 and 26.1 kg/m2, respectively). BMI, body mass index.