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Global Nutrition (Oral Session 1)

(OR01-05-25) Evaluation of Maternal Hemoglobin Cutoffs During Pregnancy and Birth Outcomes: BRINDA Project

Saturday, May 31, 2025
10:48 AM – 11:00 AM ET
Location: S220 E-G
Emerging Leaders in Nutrition Science Poster Competition
Objectives: Updated WHO case definitions for anemia during pregnancy have not been examined for associations with adverse birth outcomes in globally diverse populations. This multi-country analysis aimed to assess the relationship of existing anemia cutoffs by trimester (T) of pregnancy with birth outcomes.

Methods: Pregnant women (n=8,135) with hemoglobin (Hb) and birthweight or gestational age (GA) at birth were included from 7 trials and 1 cohort in 7 countries in the Biomarkers Reflecting Inflammation and Nutritional Determinants of Anemia (BRINDA) Project. Anemia was defined using 3 case definitions: WHO (Hb < 110 g/L T1, T3, and overall; < 105 g/L T2), INTERGROWTH-21st ( < 104 g/L T1; GA-specific cutoffs T2 and T3; < 101 g/L overall), and BRINDA 5th percentile ( < 102 g/L T1; < 98 g/L T2 and T3; < 96 g/L overall). Associations between anemia and adverse birth outcomes were evaluated using logistic regression models, adjusted for dataset and maternal age, and stratified by trimester and prenatal nutrition interventions (iron and folic acid (IFA), multiple micronutrients (MMS) or food-based supplements (FS)).

Results: 20% of infants were low birth weight (LBW), 11% were preterm (PTB), and 32% were small for gestational age (SGA). Anemia prevalence was 17% in T1, 27% in T2, and 39% in T3 using WHO cutoffs. Anemia during pregnancy was associated with higher odds of LBW [aOR (95% CI) - WHO: 1.15 (1.02, 1.31); INTERGROWTH-21st: 1.31 (1.08, 1.57); BRINDA: 1.33 (1.04, 1.71)] and PTB [1.28 (1.10, 1.48); 1.64 (1.34, 2.01); 1.98 (1.54, 2.56); respectively] but not SGA. Strongest associations were observed in T2 among women receiving IFA only (compared to MMS or FS): LBW [1.39 (1.15, 1.67); 1.36 (1.11, 1.66); 1.50 (1.18, 1.91)] and PTB [1.48 (1.20, 1.82); 1.59 (1.27, 1.99); 1.71 (1.31, 2.21)] across WHO, INTERGROWTH-21st, and BRINDA definitions, respectively, but not SGA.

Conclusions: Associations between anemia and adverse birth outcomes were consistent across case definitions for anemia in multi-country analyses but varied by trimester and prenatal nutrition interventions.

Funding Sources: Bill & Melinda Gates Foundation, Centers for Disease Control and Prevention, Eunice Kennedy Shriver National Institute of Child Health and Human Development, HarvestPlus, and the United States Agency for International Development.