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How does Blood Type impact Pregnancy and Abortion?

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Not everyone knows their blood type, and even fewer are aware of whether they are impacted by the Rh factor. It is important for everyone to know these things for the sake of their health, but it is especially important for women who are or who might be pregnant.  

What is blood type? 

There are 8 blood types: O positive, O negative, A positive, A negative, B positive, B negative, AB positive, AB negative. Blood type can be determined by “the presence or absence of certain antigens – substances that can trigger an immune response if they are foreign to the body.” Blood type is inherited, meaning that people get it from their biological parents. The type of blood that one has determines how they can give or receive a blood transfusion. For more information on blood and blood type, visit https://www.redcrossblood.org/donate-blood/blood-types.html.  

What is the Rh factor? 

 According to the American National Red Cross, “the Rh factor is an inherited protein that can be found on the surface of the red blood cell. If your blood type is positive, then your blood cells have the Rh protein. If your blood type is negative, then your blood cells lack the Rh protein.” Like blood type, the gene for Rh factor is also inherited, even though it is a recessive gene. This means that though someone’s parents may not have the Rh factor, they could still inherit the gene themselves.  

RH positive blood types are more common. RH negative blood type usually does not affect a person’s health but can affect a pregnancy. If a woman is RH negative, her baby may be positive or negative. If the baby is Rh positive, complications in pregnancy can occur. Usually, the baby’s blood and mother’s blood would not mix, but a small amount of baby’s blood could encounter the mother’s during delivery or if she is experiencing any bleeding or abdominal trauma.  If this occurs, it could cause the mother’s body to produce RH antibodies.  

This would not be a problem during a first pregnancy but could cause a serious problem for future pregnancies if those babies were RH positive.  These RH antibodies can cross the placenta and destroy the baby’s red blood cells. 

It is recommended that you receive a Rhogam injection within 72 hours after an abortion, miscarriage, or any abnormal bleeding.   Whatever your current decision is, find out your Blood Type and RH factor and if you are RH negative make sure you get Rhogam.

If a woman is pregnant, it is important for her to find out her blood type and Rh factor early on. If she is Rh negative, her baby could be positive or negative, and she should receive a Rhogam injection to prevent any Rh antibodies from forming. For Rh negative mothers, Rhogam is necessary in the case of miscarriage, abortion, ectopic pregnancy, molar pregnancy, and with bleeding that may occur during pregnancy. Rhogam is also necessary if a mother is experiencing any invasive testing such as amniocentesis and chorionic villa sampling.  

This is to protect any future pregnancy. Once you have produced the RH antibodies in your body the Rhogam will not help, and your next baby may need a blood transfusion through the umbilical cord to survive.   


  • What Is The Rh Factor? Why Is It Important?. (2022). Retrieved 7 October 2022, from https://www.redcrossblood.org/local-homepage/news/article/what-is-the-rh-factor–why-is-it-important-.html?gclid=Cj0KCQjwnP-ZBhDiARIsAH3FSRfrxCA0ChRGuttwdepEynX0pJTdSIaSWprQo4TCJ26g9S8tODHi0vsaAqQLEALw_wcB&gclsrc=aw.ds
  • Blood Types. (2022). Retrieved 7 October 2022, from https://www.redcrossblood.org/donate-blood/blood-types.html

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