Pregnancies at high risk of fetal or maternal complications. There are many factors that contribute to complications during pregnancy and delivery. Chronic medical problems in the mother, past history of repeated preterm delivery, and abnormalities of the fetus or placenta all increase the risk of complications. Women with high-risk pregnancies should be seen and treated by someone who is experienced in caring for complicated pregnancies. Usually, this is an obstetrician or a perinatologist, an obstetrician with additional training in treating high-risk pregnancy problems. In some cases a consultation with neonatologist (specialist in the care of sick newborns) can prepare you for what to expect if your baby has problems. Some hospitals have high-risk pregnancy units, where mothers stay during part of their pregnancy to receive the care they need. This is one of those conditions that is best treated by a hospital that has a high volume of these types of patients.