A new national strategy from the Netherlands aims to improve outcomes for families affected by fetal and neonatal alloimmune thrombocytopenia (FNAIT) by personalizing care and reducing unnecessary treatment, according to research published recently in SSRN.
The approach includes using a clear antibody threshold to guide therapy, helping protect fetuses from serious bleeding while avoiding overtreatment for pregnant patients who are unlikely to benefit.
FNAIT occurs when a pregnant person’s immune system makes antibodies against fetal platelets, most often anti-HPA-1a antibodies in people of European ancestry. These antibodies can cross the placenta and destroy fetal platelets, increasing the risk of bleeding.
The most severe complication of FNAIT is intracranial hemorrhage, or bleeding in the brain, which can happen before birth and may cause death or long-term disability. Until now, guidelines have varied widely between countries, leading to inconsistent care.
“The most substantial adjustment is the use of an anti-HPA-1a antibody cut-off combined with obstetric history for risk-stratification,” explained the authors of this research.
Read more about treatment and care for FNAIT
This revised protocol groups pregnancies into three risk categories: high risk for those with a prior child affected by brain bleeding, standard risk for those with prior FNAIT diagnoses without brain bleeding and undefined risk for cases found through screening or family history. The key change is using the amount of anti-HPA-1a antibody in the mother’s blood to guide treatment. Intravenous immunoglobulin (IVIg) is now started only when antibody levels reach or exceed 2 IU/mL in standard-risk and undefined-risk pregnancies.
This shift is based largely on data from the HPA-screening in Pregnancy Study, a large Dutch study showing antibody level is the strongest predictor of low platelet counts in babies. In that study, severe complications occurred only in pregnancies with antibody levels far above 2 IU/mL. Higher antibody levels were also linked to pregnancy complications, including high blood pressure, premature birth before 37 weeks and lower birthweight by roughly 187 to 530 grams.
For patients, this means fewer may need IVIg, a treatment that is effective but costly, limited in supply and associated with side effects such as headaches and rare but serious complications. Those who do need treatment can start it at the right time and dose based on their risk. High-risk pregnancies still receive early and higher-dose IVIg, because the chance of repeat brain bleeding without treatment is about 80%.
The new approach also supports vaginal delivery for carefully selected patients, especially those with a prior uncomplicated vaginal birth, rather than defaulting to cesarean delivery. Planned delivery, close monitoring and early newborn testing remain essential. Overall, the strategy aims to make care safer, more precise and easier to understand for families navigating this condition.
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