Large fetomaternal hemorrhage: prenatal predictive factors for perinatal outcome.

ABSTRACT

We sought to identify prenatal predictive factors for perinatal outcome and to estimate fetal hemoglobin (Hb) levels in large fetomaternal hemorrhages (transfused blood volume [TBV] > 20 mL) by performing a case-series study ( N = 32). Perinatal outcome was favorable (F group, N = 22) and poor (P group, N = 10 four fetal deaths, three postnatal deaths, three cases of severe anemia). Median TBV was 25 mL for the F group and 325 mL for the P group ( P < 0.0001) and median Hb concentration at birth was 15 g/dL for the F group and 5 g/dL for the P group ( P < 0.0001). Receiver operating characteristic analysis revealed that a Kleihauer-Betke test value above 2.5% was the best threshold for predicting adverse outcome, with sensitivity of 100% (95% confidence interval [CI] 76 to 100) and specificity of 96% (95% CI 77 to 100). In utero estimated Hb concentration best correlated with Hb level at birth when calculated using TBV corrected for fetoplacental weight ( P < 0.0001, R(2) = 0.874). The value obtained in the Kleihauer-Betke test was a prognostic factor, and TBV corrected for fetoplacental weight was the best biological marker for assessing fetal Hb level.