Maternal iron nutrition during pregnancy and fetal intrauterine growth

Iron is critical for maternal and fetal health; however, the effect of iron nutrition on fetal intrauterine growth remains unclear. This study aimed to investigate the associations of maternal iron nutrition during pregnancy with fetal intrauterine growth parameters among the Chinese population.

This retrospective birth cohort study included 482 pregnant women. Maternal information was collected by standard questionnaires. Maternal concentrations of serum ferritin and hemoglobin were detected. Fetal ultrasound examinations in the second and third trimesters were conducted. Quantile regression or linear regression models were applied to assess the associations.

Participants took iron supplementation in early, mid, and late pregnancy accounted for 19.1%, 40.3%, and 37.8%, respectively. Iron supplementation in the first and second trimesters and total iron intake in pregnancy were positively associated with fetal intrauterine growth parameters at some percentiles. Compared with those without iron supplementation in the second trimester, women with iron supplementation in the second trimester had 0.37 (95%CI = 0.24-0.49), 0.37 (95%CI = 0.26-0.48), 0.15 (95%CI = 0.04-0.26), and 0.52 (95%CI = 0.42-0.61) higher z-scores in fetal biparietal diameter, femur length, abdominal circumference, and estimated fetal weight at the 50th percentile in the second trimester, respectively. Maternal serum ferritin and hemoglobin concentrations in the first and second trimesters were positively correlated with several fetal growth parameters.

Fetal intrauterine growth may benefit from maternal iron nutrition in the first and second trimesters.