What Are the Consequences of Parvovirus in Pregnancy?

A pregnant mother can transmit parvovirus to her baby. This can lead to life-threatening condition, fetal anemia, due to viral infection of fetal bone marrow. This is also known as fetal hydrops, where massive edema (build up of fluid and swelling) puts great strain on the baby's heart and may cause congestive heart failure.

The risk of a pregnant woman transmitting parvovirus to her baby is 5 to 15%. The danger of transmission is greatest if the mother is infected during her first trimester and lowest after her 20th week of pregnancy. Although fetal hydrops is a serious complication, it does not usually cause birth defects. In fact, infants who receive appropriate treatment almost always survive, and their long-term development is usually normal.

What If Fetal Anemia Is Found During an Ultrasound?

If an ultrasound test shows evidence of fetal anemia, your doctor performs a technique known as cordocentesis, also known as percutaneous umbilical blood sampling (PUBS). In this procedure, your doctor removes a sample of blood from the umbilical cord in order to measure the baby's red blood cell count.

Intrauterine Blood Transfusion

If a blood test confirms that your baby is experiencing severe anemia, your doctor will perform an intrauterine blood transfusion. In this procedure, a thin needle is placed into the fetus's umbilical vein. Red blood cells are then infused through the needle directly into the fetal blood circulation.

The transfusion restores the baby's blood count and greatly reduces stress on the heart. This is a life-saving procedure and is usually performed only a few times, at most. Only an experienced doctor working in a specialized center should perform a fetal blood transfusion.

Administering a fetal blood transfusion is a technically difficult procedure. It carries a risk of fetal death, which occurs in about one out of every 100 cases. However, without treatment, the risk of fetal death is significantly higher. For those babies that have fetal hydrops, the potential benefit of a transfusion clearly outweighs the risk.