The antibody screening test is a standard blood examination in early pregnancy, checking for specific antibodies against fetal components. A common example involves the Rhesus D factor. If a Rhesus D negative mother carries a Rhesus D positive child, antibody formation can occur, especially during blood exchange at birth. These maternal antibodies could then threaten subsequent pregnancies by attacking fetal blood cells. If the test is positive, specialized ultrasound examinations are performed to monitor for fetal blood abnormalities. In cases where a Rh-negative mother carries a Rh-positive child, an antibody prophylaxis, such as the medication Rhophylac, is administered via injection to neutralize the maternal antibodies.