Maternal hematologic changes during pregnancy and the effect of iron status on preterm delivery in a west Los Angeles population

This study was conducted to document the prevalence of anemia and high hematocrit during pregnancy and examine their effect on delivering preterm in a predominantly Hispanic population. The sample consisted of women receiving prenatal care from the public health clinics in the West Los Angeles from 1983 to 1986 (n = 7589). Multivariate logistic regression was used to isolate the role of anemia and high hematocrit from other factors that may influence birth outcome. The prevalence of anemia was approximately 9% at the initiation of prenatal care and at 28-32 weeks' gestation. Only anemia at 28-32 weeks was significantly associated with a preterm birth, even after adjusting for several confounders [Adjusted Odds Ratio (AOR) 1.83 95% Cl = 1.21, 2.77]. A high hematocrit that occurred in 9.6% of the population at 28-32 weeks was inversely associated with a preterm birth (AOR 0.78, 95% Cl = 0.44, 1.39). There was little differentiation of these risk factors when analyzing the etiological pathways of a preterm birth. These results indicate for the first time in a predominantly Hispanic population that despite routine iron supplementation, anemia still occurs in pregnant women and it can predict a preterm delivery.