The difference in blood types: does it affect pregnancy?

Our blood type is affected by the RH factor, which determines whether our blood type is positive or negative. Sometimes a couple has different blood types. Find out in this article if this difference affects pregnancy and fetal health.

Cherifa Sharaf
Published on:Dec 13th 2022 |Updated on:Jun 10th 2024
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Does the difference in blood type affect pregnancy?

If the mother has a negative blood type, and her husband also has a negative blood type, then there is no effect whatsoever on the pregnancy and the fetus. However, if the father’s blood type is positive this might put the next pregnancy at risk. At birth the mother’s blood will mix with the baby’s different blood type, then the mother’s body will develop immunity to this type considering it as a foreign body that must be fought. So, in the next pregnancy, the mother’s body might attack the fetus which will most likely have a positive blood type. Such immunity attacks can cause severe complications that might lead to fetal death and termination of pregnancy.


The best option is to prevent the mother’s body from building any immunity to the different RH factors. Therefore, the OBGYNs run thorough blood tests at the beginning of the pregnancy to determine the mom’s blood type and if it is negative or positive. And cross-referencing it with the father’s blood type to make sure whether an antibodies injection is needed or not. This injection is given at the 28th week and post-birth, but in most cases, it is given only after birth.

Blood tests

I must highlight the importance of tests to determine whether the mom’s blood type is positive or negative in the early stages of pregnancy, and before delivery in case, the mom’s medical file is unavailable. Going into labor without knowing if the parents have different blood types is extremely dangerous and it affects the well-being of the next pregnancy. A mother must also be aware, and she needs to tell the medical staff if she and her husband have different blood types.

Different blood types and the next pregnancy

In case a mother with a negative blood type gives birth to a baby whose father has a positive blood type, then her body might have developed an immunity to the different blood types. In this case, she needs to inform her doctor from the beginning of her second pregnancy, to have the proper prenatal care for her case. Such pregnancies are considered high-risk and require proper follow-up and treatment, in some cases, even a fetal blood transfusion might be needed, in addition to other steps to ensure fetal survival.

Also read What is a cosmetic gynecology procedure? And do you need it?

Cherifa SharafObstetrics & Gynecology Consultant

Consultant of obstetrics, gynecology & Infertility, with years of experience in women’s healthcare. Dr.Cherifa is practicing at Qasr El Eyni Hospital/ Cairo University in addition to several other hospitals and centers in Cairo Egypt. She holds a Ph.D. in medicine from Cairo University in addition to the European Diploma of Operative Gynecology from Clermont-Ferrand, France, and Diploma of Management of Infertility from Antoine Béclère Faculty of Medicine Paris, France. Dr. Cherifa is very passionate about providing the appropriate health care to women and believes the overall health of a woman is key to her reproductive and maternal health. She is a strong believer in the importance of raising women’s awareness and educating them about everything related to health in general and reproductive health in particular.

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