Iron Supplementation in Early Pregnancy may Increase Infection Risk among Iron deficient and Iron sufficient women: Study

Results: ID women had 2.6 times greater odds for experiencing gastric illness (OR: 2.642, 95% CI: 1.116, 6.255, p = 0.027). Anaemic women (Hb < 10.5 g/dL) tended to have double the duration of respiratory illness [median 15.5 (5.0, 31.0) days] compared to non-anaemic women [median 8.0 (6.0, 12.1) days], (β: 0.167, 95% CI: -0.007, 0.342, p = 0.060) and had more incidences of vomiting throughout pregnancy (p = 0.028). In the partially adjusted models, iron sufficient erythropoiesis (non-IDE) women tended to have 2.3 times increased odds for respiratory illness (OR: 2.314, 95% CI: 0.939, 5.701, p = 0.068) and there were more incidences of fever during pregnancy in the non-IDE group (p = 0.006).

Anaemic and ID pregnant women in this largely overweight population, receiving ~ 55 mg iron daily, experience more and longer infectious morbidity, potentially related to poor iron absorption. However, although presenting with weaker evidence, iron-sufficient erythropoiesis women at early pregnancy receiving the same routine iron supplementation may have twice the risk to contract infectious respiratory illness than IDE women during pregnancy.

Reference:

Goodchild, C., Symington, E.A., Baumgartner, J. et al. Iron status at early pregnancy is associated with infectious respiratory and gastric illness in women receiving routine iron supplementation: the NuPED prospective cohort. BMC Pregnancy Childbirth 25, 657 (2025). https://doi.org/10.1186/s12884-025-07786-8