Rhesus incompatibility is almost entirely preventable through standard, modern prenatal care.
Pregnancy comes with several routine medical tests, and one of the most important is determining the blood group and Rhesus (Rh) factor of both parents.
Rhesus incompatibility occurs when a woman with Rh-negative blood is carrying an Rh-positive baby. In this situation, the mother’s immune system may recognise the baby’s Rh-positive red blood cells as foreign and begin producing antibodies against them.
The condition rarely affects a first pregnancy because the mother’s immune system is usually exposed to the baby’s blood only towards the end of pregnancy or during childbirth.
However, once these antibodies develop, they can cross the placenta in subsequent pregnancies and attack the red blood cells of another Rh-positive baby, increasing the risk of severe complications.
The Rh factor is an inherited protein found on the surface of red blood cells. People who have the protein are Rh-positive, while those who do not are Rh-negative.
Normally, the mother’s blood and the baby’s blood remain separate throughout pregnancy. However, a small amount of foetal blood can enter the mother’s bloodstream during miscarriage, ectopic pregnancy, invasive prenatal procedures, abdominal trauma, falls, road traffic accidents, labour or delivery.
If the baby is Rh-positive, this exposure can trigger the production of antibodies in an Rh-negative mother, a process known as sensitisation. Once sensitisation occurs, the antibodies remain in the mother’s bloodstream and can affect future Rh-positive pregnancies if preventive treatment is not given.
Speaking with PT Health Watch to further explain the condition, obstetrician and gynaecologist Qudus Lawal said the condition can be prevented through the timely administration of Rh immunoglobulin, commonly known as RhoGAM.
He explained that the injection prevents an Rh-negative woman’s immune system from producing antibodies against Rh-positive blood.
According to him, RhoGAM is routinely administered during pregnancy, usually between 28 and 32 weeks’ gestation, after events that may expose the mother to foetal blood, such as miscarriage or invasive procedures, and within 72 hours after delivery if the baby is confirmed to be Rh-positive.
Mr Lawal explained that Rh-positive individuals naturally tolerate Rh-positive blood, whereas Rh-negative individuals can develop antibodies after exposure to Rh-positive blood.
He noted that problems arise only when an Rh-negative woman becomes sensitised after exposure to Rh-positive foetal blood.
If left unmanaged, Rhesus incompatibility can lead to serious health problems for the baby.
Mr Lawal said these include severe foetal anaemia caused by the destruction of red blood cells, jaundice after birth and, in severe cases, pregnancy loss.
Without prompt treatment, affected babies may also develop complications associated with severe anaemia and elevated bilirubin levels.
Mr Lawal stressed that prevention begins even before pregnancy.
He advised women planning to conceive to know their blood group and undergo preconception counselling where possible.
He also highlighted the importance of early antenatal care, noting that routine blood group testing and antibody screening at the first antenatal visit allow healthcare providers to identify women at risk and provide appropriate preventive treatment.
The specialist warned that once an Rh-negative woman becomes sensitised, RhoGAM can no longer prevent the formation of antibodies.
“Being Rh-negative is not a disease,” Mr Lawal said. “It only becomes a concern if the necessary precautions are not taken.”
He added that with regular antenatal care, appropriate monitoring and timely administration of Rh immunoglobulin, the potentially life-threatening complications of rhesus incompatibility can be effectively prevented.
