Maternal Iron Intake Across Pregnancy: Impacts on Fetal Growth Trajectories

Emerging evidence suggests that experiences during fetal development have the potential to alter lifespan development. Prenatal maternal nutrition is proposed as one mechanism of fetal programming. The current study had two aims: 1) to characterize patterns of fetal growth over gestation and 2) to examine associations between prenatal maternal iron and fetal growth trajectories. We hypothesized that lower prenatal maternal iron levels would be associated with slower fetal growth trajectories and smaller birthweights. Preliminary analyses included 51 maternal-fetal pairs from a prospective, longitudinal study. Final analyses will include a larger sample size. Maternal iron levels were assessed through self-reported diet data and blood hemoglobin levels determined by medical chart abstraction. Estimated fetal weights and birthweights were also extracted. Early pregnancy maternal iron intake from one day’s diet report was positively associated with early pregnancy maternal blood hemoglobin levels (r = .36, p = .02). A quadratic effect of weeks’ gestation best fit the fetal weight data, χ2(4) = 46.58, p < .001. A linear growth model indicated that early prenatal maternal hemoglobin levels were associated with fetal weight trajectories over gestation. Contrary to our hypothesis, higher prenatal maternal hemoglobin interacted with weeks’ gestation to predict a slower rate of fetal growth (estimate = -10.13, SE = 3.53, p = .004). The study was novel in that it prospectively assessed associations between multiple indicators of prenatal maternal iron levels and fetal growth trajectories. Further research could examine if associations between maternal iron and fetal growth have implications for postnatal developmental outcomes.

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