Fetal and Neonatal Efects. Pregnancy complications that are increased with ITP include stillbirth, fetal loss, and preterm birth (Wyszynski, 2016). Platelet-associated IgG antibodies cross the placenta, and fetal death from hemorrhage occurs occasionally (Webert, 2003). he severely thrombocytopenic fetus is at increased risk for intracranial hemorrhage with labor and delivery, but fortunately this is unusual. Payne and associates (1997) reviewed studies of maternal ITP published since 1973. Of 601 newborns, 12 percent had severe thrombocytopenia with counts <50,000/�L. Six infants had intracranial hemorrhage, and in three, their initial platelet count was >50,000/�L. his is consistent with a study of 127 pregnancies in women with ITP in which 10 to 15 percent of neonates had transient ITP (Koyama, 2012).
Investigators concut that fetal and maternal platelet counts lack strong correlation (George, 2009; Hachisuga, 2014). Because of this, maternal IgG free platelet antibody levels and platelet-associated antibody levels have been evaluated to predict fetal platelet counts. Again, however, there is little concurrence with these.
Investigators have also examined the association between the speciic cause of thrombocytopenia and risk of a thrombocytopenic fetus. Four researched causes include gestational th ro m bocyto penia, hypertension -associa ted thro m bocyto penia, immune thrombocytopenia, and alloimmune thrombocytopenia. Burrows and Kelton (1993) reported neonatal umbilical cord platelet counts measuring <50,000/�L in 19 of 15,932 consecutive newborns (0.12 percent). Only one of756 mothers with gestational thrombocytopenia had an afected newborn. Of 1414 hypertensive women with thrombocytopenia, five neonates had thrombocytopenia. In contrast, of 46 mothers with immunological thrombocytopenia, four infants had thrombocytopenia. Alloimmune thrombocytopenia was associated with profound thrombocytopenia and cord platelet counts <20,000/�L. One of these fetuses died, and two others had intracranial hemorrhage.
Detection of Fetal Thrombocytopenia. Because no test accurately predicts fetal platelet counts, direct fetal blood sampling is necessary. Scott and coworkers (1983) obtained intrapartum scalp blood samples and recommended cesarean delivery for fetuses with platelet counts <50,000/�L. Dafos and colleagues (1985) reported that percutaneous umbilical cord blood sampling (PUBS) for this indication had a high complication rate (Chap. 14, p. 294). Conversely, Berry and associates (1r997) reported no complications and described poor reliability to predict severe thrombocytopenia, but noted a high negative-predictive value. Payne and coworkers (1r997) summarized six studies in which fetal blood sampling was done for platelet estimation. Of the total of 195 fetuses, severe neonatal thrombocytopenia <50,000/�L was found in 7 percent. But, serious complications from cordocentesis were noted in 4.6 percent. Because of the low incidence of severe neonatal thrombocytopenia and morbidity, fetal platelet determinations and cesarean delivery are not recommended (N eunert, 2011).