What is fetal anemia?
Fetal anemia is a condition in which a baby’s red blood cell volume falls below normal levels while the baby is developing in the womb. The condition may occur because not enough red blood cells are being produced or because they are being destroyed faster than they can be made. Red blood cells contain hemoglobin, which are molecules that carry oxygen throughout the body. The cells and organs of a developing baby need sufficient amounts of oxygen for nourishment.
Fetal anemia can cause a baby’s heart to beat faster. The heart has to work harder in order to pump more blood and oxygen through the body. In severe cases, the condition can cause the heart to fail. As the heart fails, fluid gathers in the baby’s body around the heart, lungs, and other organs. This abnormal fluid buildup is known as hydrops fetalis. If untreated, fetal anemia puts the baby’s life at risk.
Who will be on my care team?
At the Midwest Fetal Care Center, a collaboration between Children’s Minnesota and Allina Health, we specialize in individual attention that starts with you having your own personal care coordinator to help you navigate your baby’s treatment process. We use a comprehensive team approach to fetal anemia and any associated conditions. That way, you are assured of getting the best possible information by some of the most experienced physicians in the country. For fetal anemia, your care team will include a maternal-fetal specialist, a pediatric cardiologist, a neonatologist, a nurse specialist care coordinator, a perinatal social worker, and several other technical specialists. This entire team will follow you and your baby closely through the evaluation process, and will be responsible for designing and carrying out your complete care plan.
What causes fetal anemia?
Fetal anemia most commonly occurs when the mother and baby have incompatible blood types. The most frequent cause is Rh incompatibility—when the mother has Rh-negative blood type and the baby has Rh-positive blood type. The mother’s immune system treats the baby’s Rh-positive red blood cells as “foreign invaders” and sends out antibodies to fight them. The antibodies pass through the placenta and attach to the baby’s red blood cells. The baby’s own immune system then kicks in to fight the invading antibodies. That reaction leads to the destruction of many of the baby’s red blood cells.
Some congenital infections (infections passed from the mother to the baby before birth), such as parvovirus B19 (fifth disease), can also cause fetal anemia. These conditions may temporarily stop the production of the baby’s red blood cells.
Yet another cause of fetal anemia is twin anemia polyeythemia sequence (TAPS), a condition that may develop during pregnancies involving identical twins, who share a placenta. In rare cases, the blood from the shared placenta becomes unevenly distributed between the twins. One twin may receive too little blood, resulting in a low level of red blood cells.
Fetal anemia is also associated with certain genetic and metabolic disorders, such as Down syndrome (Trisomy 21) and Niemann-Pick disease.