1960s, methods were developed to perform intrauterine transfusions. As a result of these advances, the Rh disease death rate dropped to 5 percent.

With intrauterine transfusion a fetus could, for the first time, be treated directly to correct the anemia and heart failure that can occur in Rh disease. However, because the blood was transfused into the peritoneal cavity (the fluid-filled space between the abdominal wall and abdominal organs), it entered the fetal bloodstream too slowly to be very effective against hydrops, a severe, potentially fatal edema, or fluid accumulation. In the past few years, it has become possible to transfuse the fetus intravascularly, directly through the umbilical vein, and reverse hydrops.

When amniocentesis and intrauterine transfusion began, there were virtually no methods for accurately guiding a needle into the uterus. Ultrasound, in which sound waves bouncing off the fetus create a moving picture in real time, has made access to the womb substantially safer. Ultrasound and intrauterine intravascular transfusion have now lowered fetal mortality from Rh disease to 2 percent.

Ultrasound and intravascular transfusion have revolutionized fetal medicine. In addition to Rh disease, ultrasound detects life-threatening obstructions in the urinary tract, chest, and skull; diaphragmatic hernias; and cardiac dysrhythmias. Intrauterine intravascular intervention can reverse nonimmune hydrops, a fetal edema unrelated to Rh hydrops. The causative agents of this condition, including viral infections, number 100 or more. Untreated, the mortality rate can range from 50 to 90 percent.

Many fetal disorders cannot yet be treated, or treated adequately. Surgical interventions to repair severe developmental abnormalities have yielded uneven results and require further exploration. Innovative approaches are needed, which may solve such problems as inborn errors of metabolism, blood diseases, and structural abnormalities. Among technologies on the horizon, fetal gene therapy and new applications of intravenous intervention hold promise for eliminating a variety of fetal ills.

Percutaneous Umbilical Blood Sampling

KENNETH MOISE, JR.

Baylor College of Medicine, Houston, Texas

The procedure for intravenous entry into the fetal bloodstream is called by different names. The term PUBS, for percutaneous umbilical blood sampling, is commonly used in the United States; equivalent terms include cordocentesis and funipuncture. In PUBS, a needle guided by ultrasound is introduced into a blood vessel (usually the vein) of the umbilical cord to assess fetal status and treat fetal disease, particularly diseases of the blood.

PUBS was developed primarily in France, in the 1980s, to diagnose fetal toxoplasmosis, an infectious disease that can be transmitted by a pregnant wom-



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