Patient's question:
I heard that if the mother's blood type is O and the father's is not, the child's blood type might be different from the mother's, and there could be a risk of hemolysis. So, my husband and I both have blood type B. Could our baby possibly have O-type blood, and would this pose a risk of hemolysis?Doctor's answer:
There are many factors that can cause hemolysis, including physical mechanical factors, chemical drug intake, and physiological antigens. The genotypes OO0AA.AOABB.BOBABBBO are recessive, while AB is dominant. Blood type antibodies are divided into two categories: natural antibodies and immune antibodies. The ABO blood group system exists in natural antibodies. Newborns' blood does not have ABO blood group system antibodies and will develop them between 2 to 8 months after birth. Natural antibodies cannot cross the placenta, so pregnant women with incompatible blood types and fetuses generally do not allow natural ABO blood group antibodies to pass through the placenta to reach the fetus, preventing the destruction of fetal red blood cells. However, for immune antibodies, their molecules are smaller and can enter the placenta. If the mother has previously developed antibodies due to exogenous A or B antigens entering her body, pregnant women with incompatible blood types may have immune blood group antibodies enter the fetus, leading to the destruction of fetal red blood cells and causing hemolysis.