Maternal diabetes mellitus can affect a pregnant woman and her fetus in many ways. The development of preeclampsia or eclampsia is about 4 times as likely as among nondiabetic women. Infection is also more likely not only to occur but to be severe. The incidences of fetal macrosomia or death and of dystocia are increased, and hydramnios is common. The likelihood of postpartum hemorrhage after vaginal delivery and the frequency of cesarean section are both increased in diabetic women. The incidence of fetal genetic disorders such as cystic fibrosis is unaffected by diabetes.