Maternal hemoglobin levels and neonatal outcomes: the Japan Environment and Children’s Study

Low birth weight (LBW), small for gestational age (SGA), and preterm birth (PTB) are important neonatal outcomes that may affect infant morbidity and mortality. The aim of this study is to investigate associations between maternal hemoglobin (Hb) concentrations and pregnancy outcomes of LBW, SGA, and PTB. This was a prospective birth cohort study using data of the Japan Environment and Children’s Study. Participants were divided into five groups according to maternal Hb (g/dL) in the first and second trimesters: group 1, Hb Excluding 29,673, a total of 74,392 newborns (first trimester: n = 39,084, second trimester: n = 35,308) were included. We obtained adjusted odds ratios (aORs) (95% confidence intervals (CIs)) using multivariate analysis; compared with group 3 in the first trimesters, women in group 1 were at increased risk of PTB (aOR, 3.20; 95% CI, 1.69–6.09), LBW (aOR, 2.21; 95% CI, 1.19–4.09). In the second trimester, multivariate analysis revealed that, compared with group 3 in the second trimester, women in group 1 were at increased risk of PTB (aOR, 2.30; 95% CI, 1.19–4.42) and women in group 5 were at increased risk of LBW (aOR, 1.87; 95% CI, 1.24–2.81) and PTB (aOR, 1.73; 95% CI, 1.06–2.83). Elevated maternal Hb in the second trimester was associated with risks of PTB and LBW.

低出生体重儿（low birth weight, LBW）、小于胎龄儿（small for gestational age, SGA）与早产（preterm birth, PTB）是影响婴儿发病率与死亡率的重要新生儿结局。本研究旨在探讨产妇血红蛋白（hemoglobin, Hb）浓度与LBW、SGA及PTB等妊娠结局之间的关联。本研究为一项基于日本环境与儿童研究（Japan Environment and Children’s Study）数据的前瞻性出生队列研究。研究人员依据妊娠早、中期的产妇Hb浓度（单位：g/dL）将受试者分为5组；最终纳入74392例新生儿，其中妊娠早期队列纳入39084例，妊娠中期队列纳入35308例。本研究通过多因素分析计算校正后比值比（adjusted odds ratios, aORs）及其95%置信区间（95% confidence intervals, CIs）；与妊娠早期第3组产妇相比，第1组产妇发生PTB的风险升高（aOR=3.20；95%CI：1.69~6.09），发生LBW的风险亦升高（aOR=2.21；95%CI：1.19~4.09）。在妊娠中期队列中，多因素分析结果显示，与妊娠中期第3组产妇相比，第1组产妇发生PTB的风险升高（aOR=2.30；95%CI：1.19~4.42）；第5组产妇发生LBW的风险升高（aOR=1.87；95%CI：1.24~2.81），且发生PTB的风险同样升高（aOR=1.73；95%CI：1.06~2.83）。妊娠中期产妇Hb浓度升高与PTB及LBW的发生风险存在关联。