Conclusions
The prevalence of anaemia and iron deficiency was high early in pregnancy and associated with increased risk of adverse pregnancy and infant outcomes. A comprehensive approach to prevent anaemia is needed in women of reproductive age, to enhance haematological status and improve maternal and child health outcomes.
Methods
Three hundred and sixty-six women participating in a randomised trial of vitamin B12 supplementation were monitored to assess haemoglobin (Hb), serum ferritin (SF), hepcidin, C-reactive protein (CRP), and alpha-1-acid glycoprotein (AGP) during pregnancy. Women received vitamin B12 supplementation (50 µg per day) or placebo daily; all women received daily prenatal iron-folic acid supplementation. Binomial and linear regression models were used to examine the associations of maternal iron biomarkers with pregnancy and infant outcomes.
Results
Thirty percent of women were anaemic (Hb < 11.0 g/dl), 48% were iron deficient (SF < 15.0 µg/l), and 23% had iron deficiency anaemia at their first prenatal visit. The prevalence of inflammation (CRP > 5.0 mg/l: 17%; AGP > 1.0 g/l: 11%) and anaemia of inflammation (Hb < 11.0 g/dl, SF > 15.0 µg/l, plus CRP > 5.0 mg/l or AGP > 1.0 g/l: 2%) were low. Infants born to anaemic women had a twofold higher risk of low birth weight (<2500 g; risk ratio [RR]: 2.15, 95%CI: 1.20-3.84, p = 0.01), preterm delivery (RR: 2.67 (1.43-5.00); p = 0.002), underweight (WAZ < -2; RR: 2.20, 95%CI: 1.16-4.15, p = 0.02), and lower MUAC (β(SE): -0.94 (0.45)cm, p = 0.03). Similarly, maternal Hb concentrations predicted higher infant birth weight (p = 0.02) and greater gestational age at delivery (β(SE): 0.28 (0.08) weeks, p = 0.001), lower risk of preterm delivery (<37 weeks; RR: 0.76, 95%CI: 0.66-86, p < 0.0001); and higher infant MUAC (β(SE): 0.36 (0.13) cm, p = 0.006). Maternal SF concentrations were associated with greater birth length (β(SE): 0.44 (0.20) cm, p < 0.03). Findings were similar after adjusting SF concentrations for inflammation. IDA was associated with higher risk of low birth weight (RR: 1.99 (1.08-3.68); p = 0.03) and preterm birth (RR: 3.46 (1.81-6.61); p = 0.0002); and lower birth weight (p = 0.02), gestational age at birth (p = 0.0002), and infant WAZ scores (p = 0.02). Conclusions: The prevalence of anaemia and iron deficiency was high early in pregnancy and associated with increased risk of adverse pregnancy and infant outcomes. A comprehensive approach to prevent anaemia is needed in women of reproductive age, to enhance haematological status and improve maternal and child health outcomes.