A diagnosis of fetal and neonatal alloimmune thrombocytopenia (FNAIT) is most often confirmed in the newborn after delivery. Before proceeding with subsequent pregnancies after being affected by FNAIT, it is important to understand the likelihood and risks of FNAIT occurring and the potential consequences through genetic counseling.
Greater awareness of the disorder and preventative medical intervention early in pregnancy has been shown to contribute to better outcomes.
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.
What is genetic counseling?
If you’ve had a previous pregnancy affected by FNAIT or if you are aware of cases of FNAIT in your family, particularly your sister, your doctor will recommend you attend genetic counseling.
Learn more about the FNAIT care team
A genetic counselor is a healthcare professional who studies your family history and genetic risks to determine the likelihood of FNAIT occurring. This includes compiling a detailed medical history of the mother and father then performing platelet genotyping of both parties. It is important to identify if the father is homozygous or heterozygous for the incompatible HPA, as it will affect the risk assessment for FNAIT occurring in future pregnancies.
What are the benefits of genetic counseling in FNAIT?
Regardless of whether you receive FNAIT genetic counseling prior to conception or at the start of your pregnancy, you will become aware of the risk of HPA incompatibility impacting your baby. You will learn about FNAIT, where it comes from, how it is managed in utero, the monitoring and treatment options and possible outcomes. By understanding this rare blood disorder and its potential complications, you will be better prepared to navigate a pregnancy at risk of developing FNAIT.
You will also receive emotional support following genetic counseling, as you process the potential consequences of FNAIT for your baby. Your response may include fear, anxiety, stress and a feeling of helplessness. Ask your healthcare team for more help if you feel overwhelmed. Your doctor may recommend regular sessions to support you during your pregnancy.
Genetic counseling informs subsequent pregnancy care
The results of genetic testing and counseling are also helpful for the health professionals who will take care of you during your pregnancy. It will allow a tailored approach, with proactive treatment such as administering intravenous immunoglobulin (IVIG) and corticosteroids to delay or prevent the onset of severe thrombocytopenia.
While FNAIT can be potentially life-threatening, close monitoring by fetal ultrasounds and blood tests as well as early intervention in subsequent pregnancies have been shown to have positive outcomes.
