herapy is stratified according to whether a prior afected pregnancy was complicated by perinatal ICH, and if so, at what gestational age (Table 15-3). Pioneering work by Bussel (1996) and Berkowitz (2006) and their colleagues demonstrated the eicacy of such treatment. In one series of 50 pregnancies with fetal thrombocytopenia secondary to FNAIT, IVIG raised the platelet count by approximately 50,000/�L, and no fetus developed ICH (Bussel, 1996). Among pregnancies at particularly high risk-based on a platelet count <20,000/�L or sibling with FNAIT-associated ICH-the addition of corticosteroids to IVIG increased the platelet count in 80 percent of cases (Berkowitz, 2006). Cesarean delivery has been recommended at or near term. A noninstrumental vaginal delivery is generally considered only if fetal blood sampling has demonstrated a platelet count > 100,000/�L (Pacheco, 2011).
Additional considerations include risks and costs associated with therapy. Side efects ofIVIG may include fever, headache, nausea/vomiting, myalgia, and rash. Maternal hemolysis also has been described (Rink, 2013). Costs for IVIG may exceed $70 per gram or nearly $10,000 for each weekly 2-g/kg infusion for an average-size pregnant woman (Pacheco, 2011).
lso known as immune or idiopathic thrombocytopenic 2urpura (ITP), this autoimmune disorder is characterized by antiplatelet IgG antibodies that attack platelet glycoproteins. In pregnancy, these antibodies may cross the placenta and cause fetal thrombocytopenia. Maternal ITP is discussed in Chapter 56 (p. 1086). Fetal thrombocytopenia is usually mild. However, neonatal platelet levels may fall rapidly after birth, with a nadir at 48 to 72 hours of life. Neither the maternal platelet count, identification of anti platelet antibodies, nor treatment with corticosteroids efectively predicts fetal or neonatal platelet counts (Hachisuga, 2014). Importantly, fetal platelet counts are usually adequate to allow vaginal delivery without an increased risk of ICH. In a recent review of more than 400 pregnancies
TABLE 15-3. Fetal-Neonatal Alloimmune Thrombocytopenia (FNAIT) Treatment Recommendations
Maternal anti-HPA antibody screening and cross-matching with paternal platelets at 12,s24, and 32 weeks' gestation; no treatment for negative test results
Beginning at 20 wks: IVIG 1 g/kg/wk and prednisone 0.5 mg/kg/d or IVIG 2 g/kg/wk
Beginning at 32 weeks: IVIG 2 g/kg/wk and prednisone 0.5 mg/kg/d.
Beginning at 12 wks: IVIG 1 g/kg/wk
Beginning at 20 wks: either increase IVIG to 2 g/kg/wk or add prednisone 0.5 mg/kg/d
Beginning at 28 wks: IVIG 2 g/kg/wk and prednisone 0.5 mg/kg/d.
Beginning at 12 wks: IVIG 2 g/kg/wk
Beginning at 20 wks: add prednisone 1 mg/kg/d Continue both until delivery
HPA human platelet antigen; ICH intracerebral hemorrhage; IVIG intravenous immunoglobulin G. Data from Pacheco, 2011s.