Massive fetomaternal hemorrhage and fetal death: are they predictable?

To report the incidence of massive fetomaternal hemorrhage (FMH) associated with fetal death and to test the hypothesis that FMH is more likely to occur in those with risk factors for FMH.

All cases of fetal death of infants weighing > 500 gm between January 1, 1990 and December 31, 1994 were reviewed for evidence of massive FMH (> or = 2% fetal cells in the maternal circulation as measured by the Betke-Kleihauer test). Women with risk factors were compared with those without risk factors with respect to the occurrence of massive FMH.

The prevalence of massive FMH was 14 of 319 (4.4%) cases, occurring in 4 of 102 (3.9%) of those with risk factors and 10 of 217 (4.6%) of patients without risk factors (p = 0.78). Otherwise unexplained fetal death was associated with massive FMH in 5 of 141 (3.5%). Major fetal anomalies were present in 5 of 14 (35.7%) cases of massive FMH.

Clinical risk factors do not predict an increased likelihood of massive FMH. Massive FMH is associated with fetal anomalies. Betke-Kleihauer testing should be performed in all cases of fetal death, including those with anomalies regardless of the presence or absence of risk factors for FMH.