Fetal surgery is done when the fetus is not expected to live long enough to make it through to delivery or to live long after birth unless fetal surgery is performed. For instance, if a fetus has a severe form of congenital diaphragmatic hernia, in which the liver is located in the chest and lung development is severely restricted, fetal surgery is done to lessen the severity of the problem and permit the baby to live to birth to undergo further corrective surgery.
Fetal surgery can be done in various ways. Fetoscopic surgery uses a fiberoptic scope to enter the uterus through small surgical openings. The aim is to correct congenital malformations (birth defects) without major incisions and without removing the fetus from the womb. This is generally less traumatic than open fetal surgery and reduces the chances of preterm (premature) labor.
Open fetal surgery requires a hysterotomy (opening of the uterus). The fetus is partially removed from the uterus so that the area of the fetus to be operated on is exposed. After surgery, the fetus is returned to the uterus and the uterus is closed.
Surgery on the fetus may be done on the fetus after a Cesarean section, but before the cord is cut, so that the fetus is sustained by the mother's placenta and does not have to breath on its own. This method, known as an EXIT (ex utero intrapartum treatment) is employed when the fetus suffers from a congenital defect that blocks the airway. By the time the cord is cut and the baby has to breath, he or she has a clear airway.
Fetal tumors can sometimes be treated before birth. For example, benign sacrococcygeal tumors can grow very large and be life-threatening. Guided by ultrasound, radiofrequency ablation can cut off blood supply to the tumor. This hinders the tumor's growth so that the fetus can survive until it is delivered, and then after birth the tumor can be safety removed.