Demographic and Behavioral Predictors of Severe Fetomaternal Hemorrhage: A Case-Control Study.

Background: Fetomaternal hemorrhage (FMH) signifies failure of the placental barrier with whole blood transfer. Fetal anemia following FMH is associated with significant morbidity and mortality. If FMH is identified early, fetal anemia can be treated to minimize adverse outcomes. Risk factors for FMH are not known, limiting efforts to provide targeted screening for FMH.

Objective: To identify maternal and/or pregnancy characteristics associated with FMH that are recognizable prior to fetal morbidity.

Methods: This is the first published case-control study of FMH. Cases were identified from a prospectively maintained database of all hospital births between 1988 and 2010. Each case was matched to 4 controls by date and time of birth, allowing for assessment of a wide range of clinical and demographic data. Logistic regression modeling was used to assess the association between demographic and clinical characteristics and the diagnosis of FMH.

Results: A total of 23 mother-baby pairs impacted by FMH and 92 matched controls were evaluated. Compared to controls, case mothers were more likely to have private insurance and to work outside the home and at night during pregnancy. Cases were more likely to be delivered preterm, but preterm labor was not more common among cases. There was no difference in race/ethnicity of cases compared to controls.

Conclusions: Severe FMH is associated with significant morbidity and mortality of the affected neonate. Women with FMH were more likely to work outside the home during pregnancy than women with normal pregnancies. This finding has implications for third-trimester screening of pregnant women who work in strenuous fields.