How Does Blood Type Affect
How does blood type affect pregnancy?
Blood typing will always be done during pregnancy by your provider. To fill us in on exactly how blood type matters in pregnancy, I turned to long-time OB/GYN nurse Ginny Harrington.
First, I wanted to know what exactly Rh is and how the Rh factor (the + or - sign listed behind blood type) impacts pregnancy According to Ginny, “Rh Positive is when proteins appear on the surface of the blood cells. Rh Negative patients are those who do not carry the protein. When a Rh Negative woman gives birth to a Rh Positive baby, this is called Rh incompatibility. This is important, because the Rh Negative mom will treat the Rh Positive proteins found in the baby's blood as foreign, and will make antibodies to attack them (if these blood types mix in any way during the pregnancy). This is called Rhesus Disease, which can cause anemia, severe jaundice, and possible fatal conditions in the newborn.”
In addition to Rhesus Disease, there is also a condition called ABO incompatibility. This can happen when mom’s blood type is different than baby’s (if mom is blood type O, and baby is type A, B, or AB; if mom is blood type A and baby is AB or B; if mom is blood type B and baby is A or AB). If the two different blood types mix, mom’s blood can occasionally develop antibodies that fight baby’s. This attack can result in jaundice in the newborn. Enter an injection, Rhogam, that can be given during pregnancy to prevent this from happening. “This injection provides “temporary antibodies" which eliminate the immune response on the mother's part”, says Ginny. Rhogam is typically given to Rh- pregnant women between 26-28 weeks of pregnancy and again after delivery.
Generally speaking, mom’s blood and baby’s blood don’t mix during pregnancy. However, there are a few instances in which this can happen. Examples of when mixing can occur include car accidents that cause placental bleeding, undergoing a Chorionic Villus Sampling (CVS )or amniocentesis (both uncommonly used procedures that remove a small amount of amniotic fluid or placental tissue from the uterus using a thin needle), falls, and an ectopic pregnancy (a rare but dangerous type of pregnancy that can occur in the fallopian tube).