What are the risks of having a problem with Rh disease during my pregnancy?
A simple blood test can determine the Rh blood types of mother and father; roughly 1 in 7 marriages is of an Rh-negative woman to an Rh-positive man. Aspects of the father’s genetic makeup bring the overall risk down to about 10 percent. Those are overall population statistics, however. If you are an Rh-negative woman married to an Rh-positive man, your chances are either 50 percent or 100 percent of having an Rh-positive baby, depending on the genetic makeup of your husband. (There is no sure way to determine the genetics of the husband, just as there is yet no simple way to determine whether a baby in the womb is Rh-positive.) For the Rh-negative mother carrying an Rh-positive baby, there is a 16-percent chance with each pregnancy that she will be sensitized, thus putting future pregnancies at risk. Of course, that is merely an average. Barring prior blood transfusion or other exposure of the mother to blood, the first baby of a marriage is usually free from the risk of Rh disease. A
