Fetal thrombocytopenia is a condition that exists when there are a low number of platelets in the fetal blood. Platelets are important because they allow blood to clot to prevent bleeding. If the platelet number is too low there can be spontaneous bleeding that could result in fetal compromise or other problems after birth.
What causes fetal thrombocytopenia?
Texas Fetal Center Platelet Alloimunization Care Algorithm
The most common reason for fetal thrombocytopenia is an incompatibility between platelet antigens in the mother's blood and the baby's blood. This happens when the baby inherits certain types of blood antigens from the father that the mother does not have. The mother's system creates antibodies that attack the fetal platelets with these antigens. This leads to the destruction of the fetal platelets causing thrombocytopenia. Some other causes of fetal thrombocytopenia can include maternal viral infections, such as toxoplasmosis, rubella, cytomegalovirus, or parvovirus.
How is fetal thrombocytopenia diagnosed?
Fetal thrombocytopenia is most often diagnosed after a previous child has been born with signs and symptoms of a low platelet count. This can include bleeding spots (petichiae), bruising or spontaneous internal bleeding. Bleeding can occur anywhere in the fetal body, including in the brain which can lead to stroke or even death. The mother may have antiplatelet antibodies in her blood. Fetal thrombocytopenia is not usually diagnosed during routine prenatal care in a healthy mother. After an affected pregnancy, all future pregnancies need to be carefully monitored.
Once suspected, a small sample of fetal blood can be obtained from the umbilical vein to determine the fetal platelet count using ultrasound to guide and visualize the procedure. This procedure also carries a risk of pregnancy loss, infection, bleeding from the umbilical cord puncture site, or preterm labor. In some cases, fetal heart rate decelerations are observed during the procedure and emergency delivery is required. Because of this concern, this test is usually performed in a hospital setting. If both mother and fetus tolerate the procedure, they can generally go home within 24 hours.
How is fetal thrombocytopenia treated?
Fetal thrombocytopenia is monitored with ultrasound examinations and treated prenatally in several ways. The treatment plan may include maternal corticosteroids, like prednisone, or include intravenous transfusions of immunoglobulin to the mother. Some fetuses require a platelet transfusion.
What happens after delivery?
Newborns generally do well after birth. The newborn may require platelet transfusions until platelet levels are normal. The mother will need to be evaluated in future pregnancies for possible fetal thrombocytopenia.
Contact the Texas Fetal Center to make an appointment with a high-risk pregnancy doctor.
Note: This information regarding your condition is meant to be a helpful, informative introduction. Because every pregnancy is different, this may not be applicable to all cases, especially if there are additional defects. Your team of experts at the Center will provide you with information specific to your pregnancy.