Maternal-fetal medicine (MFM), also known as perinatology, is a branch of medicine that focuses on managing health concerns of the mother and fetus prior to, during, and shortly after pregnancy. Maternal-fetal medicine specialists are physicians who subspecialize within the field of obstetrics. Their training typically includes a four-year residency in obstetrics and gynecology followed by a three-year fellowship. They may perform prenatal tests, provide treatments, and perform surgeries. They act both as a consultant during lower-risk pregnancies and as the primary obstetrician in, especially high-risk pregnancies. After birth, they may work closely with pediatricians or neonatologists. For the mother, perinatologists assist with pre-existing health concerns, as well as complications caused by pregnancy.