Hematology: Vaccinating the Rh-Negative

One out of every eight marriages in the U.S. is a potentially dangerous mismatch, biochemically speaking. In these 200,000 or more marriages a year, the wife lacks the Rh factor present in most blood and is Rh-negative; the husband has the factor and is Rh-positive. The difference does not usually affect the couple's first baby. But if the baby is Rh-positive, there is a progressively increasing chance of trouble in later pregnancies. In such cases, the Rh-negative mother develops an immunity to future Rh-positive babies and may send enough damaging antibodies into the developing child's bloodstream to cause stillbirth, brain damage or a miscarriage. Rh disease kills 10,000 babies in the U.S. each year. Until recently, the only treatment was to replace virtually the entire blood supply of the fetus with a massive transfusion in the womb.

Now, after five years of testing, a new blood extract called RhoGAM has arrived on the market. It enables doctors to protect each subsequent child by merely inoculating the mother. RhoGAM consists of a gamma-globulin fraction rich in Rh antibodies. Injected into the Rh-negative mother's bloodstream no later than three days after a miscarriage or the birth of her first Rh-positive child, it curtails her immune mechanism's production of antibodies and lessens the danger to future Rh-positive children. The inoculation must be repeated after each miscarriage or birth, but the tests show that RhoGAM is 99% effective.

RhoGAM was produced by Ortho Research Foundation in collaboration with its developers, Dr. Vincent J. Freda and Dr. John G. Gorman of Columbia University and Dr. William Pollack of Ortho. Together with the necessary laboratory work, the RhoGAM treatment will add about $100 to maternity bills, but obstetricians with Rh-negative patients will undoubtedly insist on it.