women s health issues
Hemolytic Disease of the Fetus and Newborn
Diagnosis of Rh Incompatibility
Blood tests If the woman's blood contains Rh antibodies, Doppler ultrasonography At the first visit to a doctor during a pregnancy, all women are screened to determine what their blood type is, whether they have Rh-positive or Rh-negative blood, and whether they have Rh antibodies or other antibodies to red blood cells. Doctors usually assess the risk of women with Rh-negative blood becoming sensitized to Rh factor and producing Rh antibodies as follows: If the father is known and is available for testing, his blood type is determined. If the father is unavailable for testing or if he was tested and he has Rh-positive blood, a blood test called cell-free fetal nucleic acid (DNA) testing can be done to determine whether the fetus has Rh-positive blood. For this test, doctors test small fragments of the fetus's DNA, which are present in the pregnant woman's blood in tiny amounts (usually after 10 to 11 weeks). If the father has Rh-negative blood, no further testing is needed. If the father has Rh-positive blood, doctors periodically measure the level of Rh antibodies in the mother's blood. If the level reaches a certain point, the risk of anemia in the fetus is increased. In such cases, Doppler ultrasonography may be done periodically to evaluate blood flow in the fetus’s brain. If it is abnormal, the fetus may have anemia. 