Anemia before pregnancy and risk of preterm birth, low birth weight and small-for-gestational-age birth in Korean women

Background/objectives: Maternal prepregnancy hemoglobin concentration has rarely been explored as a risk of poor birth outcomes. This study examined whether women with anemia before pregnancy would be at higher risk of preterm birth, low birth weight (LBW) and small-for-gestational-age (SGA) birth. Subjects/methods: This retrospective cohort study was conducted on 70 895 Korean women who delivered a singleton in 1999, with their prepregnancy hemoglobin concentration measured at health examinations in 1997–1999. A logistic model was used to adjust for confounding variables and calculate odds ratios (ORs) and 95% confidence intervals (CIs). Results: In adjusted analysis, moderate-to-severe anemia (hemoglobin