The effects of fetal and neonatal alloimmune thrombocytopenia (FNAIT) on long-term child development depend on the severity of the symptoms during pregnancy and following delivery.
If bleeding on the brain, otherwise known as intracranial hemorrhage (ICH), occurs, it can result in permanent brain damage. This may include intellectual disability, cerebral palsy, cortical blindness and seizures. In the absence of ICH, the prognosis for the FNAIT-affected infant is good. Long-term complications have been found to occur in 14% to 26% of cases.
What is FNAIT?
Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a rare but serious condition that affects 0.1% of pregnancies in which a pregnant mother’s immune system produces antibodies against the platelets of her fetus. This occurs when a fetus inherits platelet antigens from the father that are not compatible with the mother, typically involving a protein called human platelet antigen (HPA). The mother’s immune system recognizes the fetal platelets as foreign, attacking and destroying them, leading to low platelet levels (thrombocytopenia) in the fetus or newborn.
Diagnosing FNAIT
In utero, FNAIT can be overlooked, and it is often only diagnosed if bleeding is detected on an ultrasound or following delivery. Missed or late diagnosis can have serious long-term consequences for babies affected by FNAIT.
No standard prenatal screening program exists for the diagnosis of FNAIT. In cases where FNAIT was diagnosed in previous pregnancies or a family history of the disease exists, the pregnancy is considered at risk of developing FNAIT. In subsequent pregnancies, the risk of recurrence is high and preventative intravenous immunoglobulin (IVIG) therapy and steroids are administered to the mother as early as 16 weeks’ gestation. Close monitoring of the fetus’s platelet levels track the risk to the fetus. Regular ultrasounds will check for any signs of bleeding or hemorrhage.
Possible long-term consequences of FNAIT
Newborns suffering from severe FNAIT that leads to ICH can suffer long-term neurological consequences due to irreversible brain damage. Cerebral palsy, intellectual disabilities, hearing loss and seizures are all long-term complications of FNAIT. If bleeding occurs in the eyes, this can cause blindness.
Preventing long-term complications
While FNAIT can be life-threatening or lead to long-term complications, early diagnosis and treatment can play an important role in ensuring successful outcomes. As soon as diagnosis is confirmed, the objective is to increase the fetus’s platelet levels and avoid ICH or hemorrhages in other organs such as the stomach, spinal cord, kidneys and liver.
In utero, treatment can be risky, due to the risk of uncontrolled bleeding. First-line treatment during pregnancy is intravenous immunoglobulin (IVIG) and steroids, to help suppress the mother’s immune response to her baby’s platelets. Serial intrauterine platelet transfusions (IUPT), while effective in helping to increase the fetus’s platelet count, are an invasive procedure that can lead to bleeding and even miscarriage. Early delivery via cesarean to allow postnatal treatment has shown to reduce the onset of ICH.
Following delivery, a newborn presenting with bruising, skin discoloration (petechiae or purpura) will require urgent platelet transfusions to boost platelet levels. If ICH is not present, most cases of FNAIT resolve following platelet transfusions.
