Ultrasound-guided procedures for prenatal diagnosis and therapy.

Ultrasonography has expanded the capabilities of perinatologists to examine,test, and treat the fetus. Amniocentesis and CVS are safe and widely available procedures, which can be used to diagnose a multitude of abnormalities through karyotype analysis and molecular studies. CVS allows earlier diagnosis, but both procedures can provide highly accurate results in the first half of pregnancy. Cordocentesis has fewer indications, but allows direct laboratory testing of fetal blood. Fetocentesis and fetal biopsy are reserved for limited indications, but can play a crucial role in the diagnosis of some conditions, which cannot be assessed less invasively. Fetal transfusion is an important tool in the treatment of isoimmunization, some other forms of fetal anemia, and alloimmune thrombocytopenia. Amnioreduction is a commonly used procedure for the treatment of polyhydramnios and TTTS. Multifetal reduction and selective termination offer previously unavailable options to patients carrying multiple gestations. Fetal shunts can reduce perinatal morbidity and mortality in cases of bladder outlet obstruction and hydrothorax. The limited experience with cord ligation procedures and balloon valvuloplasty suggests these relatively new procedures may serve a greater role in the future as techniques are improved. By providing guidance for all of these procedures, real-time ultrasonography has revolutionized prenatal diagnosis and therapy; it will continue to be a crucial component in evaluating and treating complicated pregnancies.