Recent findings from the U.S. Preventive Services Task Force (USPSTF) highlight that while prenatal iron supplementation reduces cases of iron deficiency and anemia during pregnancy, the impact on maternal and infant health remains uncertain.
The USPSTF’s updated evidence report, which reviewed 17 randomized trials involving over 24,000 participants, indicates that iron supplementation is linked to a lower risk of maternal iron deficiency anemia at term. This was observed in four of the trials, showing a relative risk reduction of 60% compared to no supplementation or placebo (relative risk 0.40, 95% CI 0.26-0.61), according to Dr. Amy Cantor from Oregon Health & Science University and her colleagues.
In six additional trials, iron supplementation also showed a reduced risk of maternal iron deficiency at term compared to placebo or no supplementation (relative risk 0.47, 95% CI 0.33-0.67), as reported in JAMA.
Iron deficiency anemia affects approximately 5% of pregnant individuals, posing risks for both maternal and fetal health. Despite the benefits in reducing iron deficiency and anemia, the report found no significant differences in various health outcomes, including maternal quality of life, rates of gestational diabetes, maternal hemorrhage, hypertensive disorders, cesarean delivery, preterm birth, low birth weight, or small-for-gestational-age infants, when comparing iron supplementation to placebo.
The USPSTF previously found insufficient evidence to evaluate the benefits and risks of screening for iron deficiency anemia and routine iron supplementation in pregnant women. This latest report, which includes data from five new trials, maintains that the evidence remains inconclusive regarding the benefits and harms of these practices.
In an editorial accompanying the report, Dr. Elaine Duryea and Dr. Catherine Spong from the University of Texas Southwestern Medical Center pointed out that while randomized clinical trials (RCTs) provide valuable data, they have limitations, including applicability to real-world settings and marginalized populations. They emphasized the need for large, population-based studies to address rare but impactful outcomes such as severe maternal morbidity and mortality.
Another editorial by Dr. Aaron Caughey and colleagues from Oregon Health & Science University highlighted significant gaps in knowledge. They noted the lack of consensus on screening practices and diagnostic thresholds for iron deficiency, the potential worsening of health disparities due to insufficient evidence, and the possibility that the doses used in studies may have been inadequate for effective treatment.
The report was based on a search of Ovid Medline and Cochrane databases up to May 24, 2023, including studies from high United Nations Human Development Index (HDI) countries. It covered 17 randomized trials and one observational study. Limitations of the review include the exclusion of non-English articles and potential biases in the study selection and pooling methods.
The USPSTF’s updated recommendation states that current evidence is insufficient to assess the balance of benefits and harms of screening and routine supplementation for iron deficiency and anemia in pregnant individuals. Future research should focus on addressing these gaps and improving guidelines for both prevention and treatment of iron deficiency during pregnancy.
