Improved Odds

A prenatal test for hemophilia

Hemophilia, the bleeder's disease, evokes images of royal princes who suffered from this genetic malady, and of the Russian monk Rasputin, who gained influence over Nicholas and Alexandra by convincing them that he could control their son's bleeding. Such aristocratic associations have tended to obscure the grim fact that hemophilia strikes ordinary mortals as well. It imposes enormous physical, emotional and financial burdens on both sufferer and family.

The rare, inherited blood disorder affects males primarily, and afflicts some 25,000 Americans. Because most hemophiliacs lack a blood-clotting substance known as factor VIII, they may bleed uncontrollably after slight injuries or from such ordinary events as losing baby teeth. Frequently there is bleeding into joints, leading sometimes to crippling. Today many hemophiliacs are successfully treated with injections of factor VIII, but that is therapy, not a cure. It is also expensive--$6,000 to $26,000 a year. For many couples with a family history of hemophilia, the prospect of raising a child with the disease is more than they can face.

Some families thus choose not to have children at all. Others, hoping that the baby will be a girl, go ahead with a pregnancy. But once they learn through amniocentesis that the fetus is male, they will opt for an abortion. Even though there is a fifty-fifty chance that the boy will not be a hemophiliac, medicine has had no way of telling whether those odds would be in the parents' favor.

Now doctors at Yale, the University of Connecticut and Case Western Reserve report they have devised a prenatal blood test that may avert those heart-rending abortions. Once amniocentesis determines that a woman is carrying a male child, doctors use a technique called fetoscopy to obtain a sample of the baby's blood. They make an incision in the woman's abdomen, then insert a tubular fiber-optic device to locate one of the baby's blood vessels on the placenta. Using a tiny needle, they withdraw a few drops of the baby's blood, which is analyzed by radioimmunoassay techniques for factor VIII. To date, investigators have used the experimental procedure on eight women, all of whom had family histories of severe hemophilia. In four cases the tests showed that the fetus carried almost none of the clotting factor. Abortions were performed; tests later confirmed that the fetuses had severe hemophilia. In the other four cases, because the tests revealed that the fetus was normal, the pregnancies continued, and three of the women have already given birth to healthy boys.

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