What constitutes fetal therapy?
Improvements in ultrasound technology have made possible detailed visualization of the fetus and uterus. The real-time aspect also means that ultrasound can be used for guiding therapies. Fetal therapy had its beginnings with fetal transfusion for Rh incompatibilities. The techniques of intraperitoneal blood transfusion and sampling of umbilical vein blood were developed in the 1960s to 1970s and used ultrasound guidance. In the 1980s, ideas about surgery on the fetus were tested in laboratory experiments on animals and eventually brought to human fetuses. The first reported open fetal surgical procedure was performed in 1982 by Harrison and colleagues. They created bilateral ureterostomies in a 21-week fetus that had bilateral hydronephrosis. The procedure was a technical success, but the neonate succumbed to the (at the time) unrecognized problems of renal dysplasia and pulmonary hypoplasia. Through the following decade, fetal surgical treatments were developed, and success rates increased.
Fetal therapeutic techniques include:
- • Open fetal surgery (hysterotomy, performing the surgery, and closing the hysterotomy).
- • Interventional techniques (ultrasound-guided shunt placements and fluid aspiration).
- • Ex-utero intrapartum therapy (EXIT). This is performed for management of conditions that obstruct the fetal airway or compromise breathing. The fetus is delivered via caesarian section, but the umbilical cord is not ligated. Surgery is then performed on the fetus while still connected to the placenta so that the fetus continues to be supplied oxygenated blood via the placental connection, giving surgeons time to relieve the airway obstruction. Once the airway is established (or the surgical procedure is finished), the delivery is completed.
- • Fetal therapy also includes medical management, which is an integral part of treatment of the fetus whether or not the surgical methods are employed. While fetal therapy begins with the mother and fetus, in most instances, treatment is continued for the neonate, so centers that perform fetal therapeutic procedures have the support of neonatal intensive care.