An incongruity between the blood group of an Rh-negative pregnant woman and that of her baby. Under specific conditions, this discrepancy can result in hemolytic disease of the newborn.
The Rh system relies on the existence or absence of certain elements within the blood, with the pivotal one being the D antigen (a substance capable of provoking an immune reaction). Blood classified as Rh-positive contains the D antigen, while Rh-negative blood lacks it. The determination of blood type is governed by genes, which are the fundamental units of heredity.
A prevalent source of rhesus incompatibility arises when an Rh-negative woman comes into contact with her Rh-positive baby’s blood during childbirth. Generally, the initial pregnancy involving an Rh-positive baby doesn’t encounter issues. Nonetheless, the woman might generate antibodies (proteins produced by the immune system) targeted at the D antigen. In a subsequent pregnancy involving an Rh-positive baby, these antibodies could potentially traverse the placenta and assault the red blood cells of the fetus.
An Rh-negative woman can also develop sensitivity to Rh-positive blood if she experiences a miscarriage, abortion, or undergoes amniocentesis, during which the Rh-positive blood from the fetus enters her bloodstream. Additionally, a placental abruption, marked by the detachment of part or all of the placenta from the uterine wall, can lead to the exchange of blood between the mother and the fetus.
Rhesus incompatibility has become infrequent due to the standard administration of anti-D (Rh0) immunoglobulin injections to Rh-negative women throughout their pregnancy and during childbirth. This immunoglobulin neutralizes any of the baby’s blood cells that may have entered the mother’s bloodstream before she becomes sensitized to them.
Rh-negative women are also administered anti-D (Rh0) immunoglobulin after experiencing a miscarriage, abortion, amniocentesis, or undergoing any procedure that could potentially lead to the mother being exposed to fetal blood cells.