Low first-trimester hemoglobin and low birth weight, preterm birth and small for gestational age newborns

ObjectiveTo examine the relationship between first-trimester hemoglobin (Hb) concentration and risk of low birth weight (LBW), preterm birth and small for gestational age (SGA).MethodsData were obtained from a population-based prenatal care program in China. A total of 88,149 women who delivered during 1995–2000 and had their Hb measured in the first trimester were selected as study subjects.ResultsThe prevalence of anemia (Hb < 110 g/L) was 22.1% in the first trimester. The risk of LBW, preterm birth and SGA was increased steadily with the decrease of first-trimester Hb concentration. After controlling for confounding factors, women with Hb 80–99 g/L had significantly higher risk for LBW (OR = 1.44, 95% CI 1.17–1.78), preterm birth (OR = 1.34, 95% CI 1.16–1.55) and SGA (OR = 1.13, 95% CI 0.98–1.31) than women with Hb 100–119 g/L. No elevated risk was noted for women with Hb ≥ 120 g/L.ConclusionLow first-trimester Hb concentration increases the risk of LBW, preterm birth and SGA.