Selection of delivery method in pregnancies complicated by autoimmune thrombocytopenia: a decision analysis

To compare three common strategies for selecting delivery methods in term pregnancies complicated by immune thrombocytopenia by contrasting their effects on the number of severely thrombocytopenic neonates delivered vaginally and total cesarean rates.

We used decision analysis to compare three strategies to select delivery method in women with autoimmune thrombocytopenia, funipuncture at term, intrapartum fetal scalp platelet sampling with delivery mode decisions based on platelet count in the first two strategies, and no testing of fetal platelets with delivery mode determined by standard obstetric criteria. We assumed that the goal of each strategy was to minimize the number of severely thrombocytopenic neonates delivered vaginally while maintaining an acceptable cesarean rate. Severe thrombocytopenia was defined as under 50,000 platelets per microL. Probabilities with ranges (used in sensitivity analyses) were derived from the medical literature.

Of the two testing strategies, funipuncture was clearly preferable. Funipuncture resulted in zero cases of severely thrombocytopenic neonates delivered vaginally (as did scalp sampling), with a lower overall cesarean rate compared with fetal scalp sampling (36.6% versus 69.1%). Compared with the no-testing strategy, the funipuncture strategy reduced the number of severely thrombocytopenic neonates delivered vaginally (0 versus 82 per 1000) with a modest increase in the cesarean rate (1.9 cesareans to prevent vaginal delivery of one severely thrombocytopenic neonate).

Fetal scalp sampling should be abandoned in favor of funipuncture when testing for thrombocytopenia.