What every woman should know about Rh-negative blood and pregnancy

About 5 to 7 per cent of Indians have Rh-negative blood, far lower than the 15 per cent seen in Western populations. The blood type itself causes no health problem. For a woman planning a pregnancy, however, it is information her obstetrician needs to know from the first visit.

The Rh factor refers to a protein, the RhD antigen, found on the surface of red blood cells. People who carry the protein are Rh-positive. Those who do not are Rh-negative. Difficulties arise in only one situation: when an Rh-negative mother is carrying an Rh-positive baby. This is more likely to happen when the father is Rh-positive and the baby inherits his blood type.

During pregnancy, delivery, miscarriage or any procedure that disturbs the placenta, a small amount of the baby's blood can enter the mother's circulation. Her immune system sees the unfamiliar Rh protein as foreign and begins producing antibodies against it. The process is called sensitisation.

The first pregnancy is usually safe because sensitisation takes time. The real concern is the next pregnancy. If the second baby is also Rh-positive, the mother's existing antibodies can cross the placenta and attack the foetus's red blood cells. The result is haemolytic disease of the foetus and newborn, which can cause severe anaemia, jaundice, brain damage or stillbirth.

An injection of anti-D immunoglobulin stops the mother's body from producing antibodies. Without it, 16 per cent of at-risk pregnancies develop complications. With it, the figure drops to 0.1 per cent.

The Federation of Obstetric and Gynaecological Societies of India (FOGSI) recommends that every Rh-negative pregnant woman receive an anti-D injection at 28 weeks of pregnancy and a second dose within 72 hours of delivery if the baby is Rh-positive. The injection is also needed after a miscarriage, an abortion, an ectopic pregnancy or any invasive procedure such as amniocentesis or chorionic villus sampling. Even minor trauma to the abdomen during pregnancy can warrant a dose.

Every woman should know her blood group before she conceives. The partner's Rh status should also be checked, since an Rh-negative father removes the risk. Antenatal visits should not be skipped, because the indirect Coombs test, which screens for antibodies in the mother's blood, is part of standard care.

In India, access remains uneven. Anti-D is not always stocked at smaller hospitals, and many women in rural areas are not screened early enough in pregnancy. An Rh-negative woman should confirm that her chosen facility administers the injection as per the FOGSI recommendations to optimise pregnancy outcomes.

Dr. Ameya C Purandare President , AMOGS 2026-28 Consultant Obstetrician & Gynaecologist Purandare Hospital