Obesity-related comorbidities such as gestational diabetes and hypertension have the potential to affect at least 25% of women in the United States. Midwives have been caring for and collaboratively managing these conditions in nonobese women for decades. Prenatal weight gain advice should be based on pregravid body mass index and aim for the lower end of the 1990 Institute of Medicine prenatal weight gain ranges. Obese women may require extra ultrasound and blood glucose testing during pregnancy. Pregnancy complicated by obesity may limit the place and style of birth. Midwives can integrate management techniques into the perinatal care of women whose body mass indices exceed 29 to reduce risk and future disease for mothers and newborns.