Impact of Maternal Iron Deficiency in Early Pregnancy on Neonatal Iron Status and Neurodevelopment at Two Years of Age: a Prospective, Maternal-Infant Cohort Study

Background: Iron deficiency during pregnancy has potentially serious health consequences for both the mother and her offspring. Few prospective studies have considered the impact of maternal nonanemic iron deficiency in early pregnancy on offspring health outcomes. Objective: The objective of this study was to explore the impact of maternal iron deficiency in early pregnancy on neonatal iron status at birth and neurodevelopment at 2 y of age. Methods: In a low-risk, primiparous nonanemic maternal-infant cohort, ferritin, soluble transferrin receptors, and inflammatory markers (C-reactive protein and α-glycoprotein) were measured at 15- and 20-weeks of gestation and in umbilical cord blood. Bayley Scales of Infant and Toddler Development (BSID-III) and the Child Behavior Checklist were assessed at 2 y. Results: Participants with complete longitudinal data from 15 weeks of gestation to 2 y (n = 189) were Caucasian (96.8%), highly educated (78.8% university graduates), with singleton pregnancies. At 15-weeks of gestation, 3.2% had ferritin <15 μg/L and 18.5% had ferritin <30 μg/L, which increased to 8.5% and 42.3% <15 and <30 μg/L, respectively, at 20-weeks. Iron depletion (cord ferritin <76 μg/L) was observed in 7.4% of newborn infants. Cord ferritin concentrations were 42.3 μg/L lower in infants born to iron deficient mothers (using maternal ferritin <30 μg/L threshold) at 15-weeks, compared with those with iron sufficient mothers. Children born to mothers with ferritin <30 μg/L at 15- and 20-wk had lower BSID-III language [Estimated β (95% confidence interval), 15-wk: −7.3 (−14.0, −0.4), 20-wk: −6.3 (−11.0, −1.3)] and motor [15-wk: −5.8 (−11.0, −1.1), 20-wk: −4.0 (−7.8, −0.3)] composite scores at 2 y than those with iron sufficient mothers. Conclusions: Maternal nonanemic iron deficiency in early pregnancy was associated with low iron status at birth and worse language and motor outcomes at 2 y of age. This new evidence highlights the need to consider screening for iron deficiency early in pregnancy, even in well-resourced settings. This trial was registered at clinicaltrials.gov as NCT01891240.