The World Health Organization (WHO) estimates that over 2 billion people, roughly 30% of the world’s population, are affected by anemia and at least 50% of pregnant women are anemic. Although anemia has been shown to affect women in both high- and low/middle-income nations, the major burden of disease is found in low/middle-income countries. The association of both the presence of anemia and its severity to maternal and neonatal outcomes has not been well characterized. Limited data suggest that severe anemia is associated with an increased risk of low birthweight, but that mild anemia may protect against low birthweight. A study of 421 pregnant women in India indicated that there is a high prevalence of anemia (85%) in this population as well as a correlation between anemia severity and low birthweight as well as earlier gestational age at delivery. Other studies have reported conflicting data on the effect of anemia on preterm birth. A metanalysis reported in the year 2000 showed an increased risk of preterm birth among women who experienced anemia in the first trimester with an overall odds ratio of 1.32. However, many of the studies reviewed in the meta-analysis were small and a high degree heterogeneity in outcomes was noted. While this meta-analysis was inconclusive, the authors commented that in a few of the included studies, hemoglobin 8–8.5 g/dl was associated with an increased risk of poor outcome. One study found a linear relation between hemoglobin and the risk of stillbirth in a multi-ethnic population in England. A retrospective cohort study in Scotland found that hemoglobin <10 g% was associated with increased risk of stillbirth.
By: Parks S, Hoffman MK, Goudar SS, Patel A, Saleem S, Ali SA et al.