Project Details

Iron-deficiency and non-iron-deficiency anemia in pregnancy and infant health in India

Lindsey Locks, ScD, MPH

Summary

BACKGROUND: The global burden and distribution of iron deficiency is largely unknown. Most studies in Low and middle Income Countries (LMICs) use hemoglobin/anemia as a proxy for iron deficiency; however, hemoglobin is neither a sensitive nor specific measure of iron deficiency. Interventions preventing anemia in pregnant women in India and globally focus on supplementation with iron and folic acid; however, these interventions have had limited success in reducing the burden of anemia in pregnancy and low birth weight (LBW) in infants. GAP: This study will assess the prevalence of iron deficiency anemia (IDA) and non-iron deficiency anemia (NIDA) in Eastern Maharashtra and their associations with infant health outcomes (birth weight, gestational age at birth, weight-for-gestational-age z-score and infant hemoglobin concentration at 6 weeks). HYPOTHESES: Hypothesis 1: Iron Deficiency Anemia (IDA) will have a stronger association with infant health outcomes than non-iron deficiency anemia (NIDA). Hypothesis 2: Anemia during the first trimester will have the strongest association with poor infant health outcomes; and anemia during either the 1st or 3rd trimester will be associated with poor infant health outcomes. METHODS: This study is nested in the NICHD Global Network for Women’s & Children’s Health Research Maternal Newborn Health (MNH) registry - a prospective, observational population-based registry. The Thrasher-supported sub-study will select a representative sample of n=200 mothers in Eastern Maharashtra and will add: 1) blood draws in the first trimester to assess iron status; 2) an additional study visit in the 3rd trimester to assess hemoglobin; 3) a heel prick for infant hemoglobin at 6 weeks, and 4) new questionnaires on maternal diet and adherence with iron-folic acid supplementation. RESULTS: In the 1st trimester, mean Hb concentration and anemia prevalence using capillary specimens were 10.9±1.5g/dL and 51.1%; venous blood specimens estimated 11.3±1.3g/dL and 37.5% anemia prevalence. The prevalence of iron, vitamin B12 and folate deficiencies were 40%, 30% and 0%, respectively. Among women with anemia in the 1st trimester (venous blood), 56% had concurrent ID indicating that their anemia may be amenable to iron supplementation. By the 3rd trimester, mean Hb from capillary specimens had declined to 10.1±1.35g/dL and anemia prevalence increased to 70.7%, despite 99.4% of mothers reporting receipt of iron-folic acid (IFA) supplements and 83.9% reporting IFA consumption the previous day. Significant predictors of anemia in the 1st trimester (both venous and capillary) included gestational age and inflammation-adjusted serum ferritin. For 3rd trimester anemia, significant predictors included 1st trimester height, BMI and IFA consumption during the 3rd trimester (but not 1st trimester micronutrient biomarkers), indicating that supplementation over the course of pregnancy may have influenced micronutrient status and anemia risk. Compared with normal Hb concentrations, mild anemia, moderate anemia, and high capillary Hb concentrations in the first trimester were significantly associated with lower birthweight (β: -147.7 g, p=0.003; β: -77.7 g, p=0.001; and β: -236.0 g, p=0.02) and birthweight-for-gestational age percentile (β: -7.3, p=0.03; β: -8.4, p=0.004; and β: -8.9, p=0.01 respectively). Mild anemia in the third trimester was significantly associated with lower gestational age at birth (β: -0.5 weeks, p<0.0001). With regard to anemia-related micronutrient biomarkers, higher serum ferratin concentrations in the first trimester were significantly associated with higher infant birthweight (β: 2.0 g, p=0.04) and gestational age at birth (β: 0.01 weeks, p<0.0001). Finally, vitamin B12 deficiency in the first trimester was significantly associated with lower infant Hb concentrations at six weeks of age (β: -0.5 g/dL, p<0.0001). IMPACT: Our findings highlight the severity of the burdens of anemia and micronutrient deficiencies during pregnancy in Eastern Maharashtra, and their associations with birth outcomes. Preventing and managing anemia in pregnancy in India will require strengthening both clinical and community-based strategies targeting iron deficiency, as well as other causes of anemia.