Learn The BasicsFetal and neonatal alloimmune thrombocytopenia (FNAIT) is a rare disease that is most often mild, but in severe cases, it can lead to brain damage or even death.
Prognosis of mild FNAIT
Babies born with FNAIT who do not have serious bleeding typically recover completely and usually do not need further care other than routine follow-up visits after leaving the hospital.
This is because after delivery, the mother’s antibodies that attack her baby’s platelets, thereby causing FNAIT, are rapidly cleared from the baby’s circulation, and platelet counts return to normal.
In these cases, the children affected do not have low platelet counts later in life.
Prognosis of severe FNAIT
Still, FNAIT may lead to serious complications, the most severe of which is intracranial bleeding (ICH). This is a type of stroke in which the blood pools between the brain and the skull preventing oxygen from reaching the brain.
ICH occurs in 10 to 25% of FNAIT cases and can have lifelong neurological effects. In the most severe cases, FNAIT can be fatal.
Around 20 to 70% of babies with ICH experience lifelong neurological deficits. These may include cerebral palsy, intellectual disability, seizures and hearing loss.
Other complications of FNAIT may include bleeding in other vital organs such as the gastrointestinal tract, causing symptoms such as bloody stools and blood in the lungs or eyes, which may lead to blindness.
Factors affecting prognosis
It is not known why some cases of FNAIT are so mild while others may have devastating effects.
Some researchers have suggested that the levels of antibodies in the blood of the mother during pregnancy may affect the severity of thrombocytopenia or low platelet counts in the baby, increasing the risk of complications like ICH.
One Norwegian study has suggested that antibody levels of 3 IU/mL during pregnancy could predict severe thrombocytopenia in the newborn baby. The researchers stated this value is used to decide where and how delivery should take place.
However, other researchers failed to find such a link between antibody levels in the mother’s blood and the severity of thrombocytopenia in the newborn baby.
In general, however, a fetus who has an older sibling who experienced ICH due to FNAIT before birth has an increased risk of also having ICH before birth.
Survival rate
For fetuses and infants who do not develop ICH, the survival rate is overall very positive.
Survival rates are closely linked to whether ICH occurred. The survival rate of babies with ICH due to FNAIT varies between 52% and 65%.
Future pregnancies
If a woman had a pregnancy affected by FNAIT, the risk of her second pregnancy also being affected is very high, at 90%.
If someone has previously had a fetus affected by ICH, she should be treated with intravenous immunoglobulin (IVIG) starting at around 12 to 16 weeks of the pregnancy to dampen her immune system and reduce the risk of her second fetus also having ICH.
If a woman is at risk of FNAIT but her first child did not have ICH, she will likely be treated IVIG between 20 and 24 weeks of the pregnancy.
