The risk of developing hemolytic disease of the fetus and newborn (HDFN) during pregnancy may be greater in older women, due to factors such as age, existing health conditions and past pregnancies.
Early detection, close prenatal monitoring and timely medical intervention play a key role in ensuring the best outcomes for mother and baby.
Risk factors for maternal sensitization
When fetal red blood cells mix with a mother’s blood, the mother becomes alloimmunized, and this can trigger the production of maternal antibodies to the fetus’s red blood cells. If these antibodies cross the placenta and attack the fetal red blood cells, it can eventually lead to HDFN in the fetus.
Learn more about HDFN causes and risk factors
Here are some of the ways fetal blood can come into contact with maternal blood in the case of older pregnant women:
Pre-existing conditions
There are several pre-existing conditions that can affect the health of pregnant older women, including hypertension, type 2 diabetes, thyroid or autoimmune disorders and other cardiovascular conditions. Conditions such as hypertension and preeclampsia may also develop during pregnancy.
Pre-existing conditions can impact the overall health of an older woman during pregnancy, causing the pregnancy to be treated as high-risk. However, the only conditions shown to increase the risk of HDFN are hypertension and preeclampsia, as they can lead to a greater risk of fetomaternal hemorrhage, where fetal blood leaks into the maternal circulatory system.
While less common, another risk factor may be a history of regular blood transfusions. There is a chance that foreign red blood cell antigens lead to the development of antibodies that trigger HDFN.
Medical procedures
Pregnancies in older women are considered higher-risk and require closer monitoring and additional testing to have a clearer picture of the health of the fetus. Procedures such as amniocentesis or chorionic villus sampling (CVS) also increase the risk of maternal alloimmunization.
Previous pregnancies
Alloimmunization can occur during pregnancy or birth, particularly during a cesarean. In older women, the chance is higher that there have been past pregnancies and that alloimmunization has occurred in a previous pregnancy. Maternal antibodies remain in the mother’s system between pregnancies, regardless of age.
The effective management of a pregnancy in an older woman at risk of HDFN requires specialized prenatal care. As a potentially high-risk pregnancy, regular blood tests to check for maternal antibodies and ultrasounds to closely monitor the fetus for any signs of fetal anemia will ensure early detection and treatment.
Sign up here to get the latest news, perspectives, and information about HDFN sent directly to your inbox. Registration is free and only takes a minute.
