Association of hemoglobin levels in the first trimester and at 26 to 30 weeks with fetal and neonatal outcomes: A secondary analyses of the global network for women's and children's health's ASPIRIN trial

Objective: Limited data are available from low- and middle-income countries (LMICs) on the relationship of hemoglobin (HGB) levels at different times in pregnancy to adverse outcomes. We evaluated the association of HGB levels in nulliparous women at two times in pregnancy with pregnancy outcomes.Design: ASPIRIN Trial data were used to study the association between HGB levels measured at 6⁺⁰ to 13⁺⁶ weeks and 26⁺⁰ to 30⁺⁰ weeks gestational age (GA) with fetal and neonatal outcomes.Setting: Obstetric care facilities in Pakistan, India, Kenya, Zambia, The Democratic Republic of the Congo and Guatemala POPULATION: 11,976 pregnant women METHODS: Generalized linear models were used to obtain adjusted relative risks and 95% CI for adverse outcomes.Main outcome measures: Preterm birth, stillbirth, neonatal death, SGA and birth weight Results: The mean HGB at 6⁺⁰ -13⁺⁶ weeks GA and at 26-30 weeks GA were 116 g/L (sd 17) and 107 g/L (sd 15) respectively. In general, pregnancy outcomes were better with increasing HGB. At 6⁺⁰ -13⁺⁶ weeks GA, stillbirth, SGA and birth weight Conclusions: Both lower and some higher HGB concentrations are associated with adverse fetal and neonatal outcomes at 6⁺⁰ -13⁺⁶ weeks and at 26-30 weeks GA, although the relationship with low HGB levels appears more consistent and generally stronger.