The Impact of Maternal Anemia on Perinatal Mortality: A Population-based, Prospective Cohort Study in China

PURPOSE: To evaluate whether anemia during pregnancy is associated with increased risk of stillbirth and neonatal death. METHODS: A prospective cohort study, using data from a population-based pregnancy-monitoring system in 13 counties in East China (1993-1996) was conducted. Singleton live births (n = 163,313) and stillbirths (n = 1,354) delivered at 20 to 44 weeks to women with one or more hemoglobin measures during pregnancy were included. Stillbirth and neonatal mortality rates by anemia status in each trimester were estimated. Multivariable Cox proportional hazards regression models were used to evaluate the association between hemoglobin levels and mortality risk. RESULTS: The stillbirth rates were 6.2 and 9.2 per 1,000 births in women with and without anemia (hemoglobin < 10 g/dL), respectively. The protective effect of anemia was mainly in the third trimester. Hemoglobin of 9 g/dL in the third trimester was associated with reduced risk (hazard ratio [HR], 0.8; 95% confidence interval [CI], 0.7-0.97). Maternal anemia was not associated with neonatal mortality. CONCLUSIONS: Although maternal anemia was not associated with increased risk of mortality in the neonatal period, women with anemia during the third trimester had lower risk of stillbirth. Ann Epidemiol 2009;19:793-799. (C) 2009 Elsevier Inc. All rights reserved.