Long-term association between maternal preconception hemoglobin concentration, anemia, and child health and development in Vietnam

Background
The long-term association between preconception maternal hemoglobin (Hb) concentrations and child health and development is unclear.

Objectives
We examined associations between maternal preconception Hb concentrations and anemia with 1) birth outcomes (weight, length, preterm, gestational age, small for gestational age); 2) child Hb at 3 mo, 6 mo, 12 mo, and 24 mo; and 3) motor and mental development at 12 mo and 24 mo (Bayley scales for infant development) and cognitive functioning at 6–7 y (Wechsler Intelligence Scale for Children).

Methods
We used data from a randomized controlled trial (PRECONCEPT) conducted in Vietnam. Over 5000 women who were intending to conceive were recruited, and offspring were prospectively followed from birth (n = 1599) through 6–7 y (n = 1318). Multivariable linear and logistic regressions were used to assess the association between preconception Hb or anemia (Hb < 12g/dL) on child health and development outcomes, adjusted by supplementation group (tested for interactions) and confounding at maternal, child, and household levels.

Results
At preconception enrollment, 20% of the women were anemic. Maternal preconception Hb was positively associated with child Hb at 3 mo (0.06; 95% CI: 0.01, 0.12), 6 mo (0.08; 95% CI: 0.03, 0.13), 12 mo (0.10; 95% CI: 0.04, 0.15), and 24 mo (0.07; 95% CI: 0.02, 0.12). Likewise, maternal preconception Hb was associated with reduced risk of child anemia at 6 mo (0.89; 95% CI: 0.81, 0.98), 12 mo (0.81; 95% CI: 0.74, 0.89), and 24 mo (0.87; 95% CI: 0.79, 0.95). Maternal preconception anemia was negatively associated with cognition (−1.64; 95% CI: −3.09, −0.19) and language development (−1.61; 95% CI: −3.20, −0.03) at 24 mo. Preconception Hb was not associated with birth outcomes or cognitive outcomes at 6–7 y.

Conclusions
Maternal preconception Hb was associated with child Hb across the first 1000 d of life. However, preconception Hb was not a significant predictor of birth outcomes or cognitive outcomes at 6–7 y in this cohort from Vietnam.