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Blood mismatch in pregnancy

In fact, in order for the baby to be affected by blood mismatch, the baby's blood type and the mother's must be incompatible, that is, the baby must have blood type characteristics similar to the father.

In this case, if the father is Rh (+) while the mother is Rh (-), and the baby is Rh (+) like his father, there is a blood mismatch. Since the baby's blood type will be determined after birth, the mother (-) and the father (+) should act as if there is a blood mismatch.

Mechanism of Action

Blood cells that pass from the baby with RH (+) to the mother's bloodstream during childbirth or miscarriage lead to the formation of Rh antibodies in the mother with Rh (-). These antibodies attack rh (+) blood cells circulating in the blood. If the Rh (+) baby is formed during subsequent pregnancies, rh antibodies formed in the mother begin to break down the baby's blood cells by moving from the placenta to the baby's bloodstream. Therefore, blood mismatch is risky not for the first babies, but for subsequent babies, and the treatment to be carried out is to protect future pregnancies.

The blood cells of the baby causing the blood mismatch often pass into the mother's bloodstream during childbirth or cesarean section. Sometimes interventional processes such as miscarriages and amniosynthesis can also cause this transition. In rare times, if a Rh (-) woman is given Rh (+) blood by improper application, there is a risk of blood mismatch in the first babies.

Clinical Symptoms and Diagnosis

When Rh antibodies formed in the mother pass to the baby, it causes the baby's blood cells to break down and anemia (anemia) occurs in the baby. As a result of the anemia developing in the baby, the baby's heart begins to work harder to pump the blood, after a while heart failure develops and fluid accumulation begins in the body cavities. The so-called "hydrops" table is formed by the accumulation of fluid under the baby's abdominal cavity, rib cage, skull and skin. Depending on the severity of the disease and the severity of the anemia in the baby, even the death of the baby in the womb can be seen.

It is very important to know the blood type of the candidates for mother and father in the diagnosis of blood mismatch. If the mother is Rh (+), the father's blood type loses importance. If the mother is Rh (-) and the father is Rh (+), rh antibodies that should not normally be in the mother's blood should be screened with a test called "indirect coombs" during pregnancy follow-up. When there is a birth, the baby's blood type should be examined immediately and the necessary precaution should be taken immediately.


In the presence of RH nonconformity (if the mother is Rh (-) and the father is Rh (+), an "anti-D injection" should be performed at the 28th week of pregnancy to prevent the mother from forming antibodies to the Rh factor. This needle, commonly referred to as a "mismatch needle", should be re-administered within the first 72 hours if the baby's blood type is positive after birth.

In cases such as miscarriage, external pregnancy, abortion or severe bleeding during pregnancy, it is also right to give an anti-D injection. Following procedures such as amniocenthesis, cordosynthesis, corion villis biopsy, which are interventional procedures for diagnostic purposes, anti-D injection is extremely important for the healthy continuation of pregnancy.

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