USPSTF: Iron Deficiency Screening, Supplementation in Pregnancy Lacks Evidence

Wanda K. Nicholson, MD, MPH, MBA

Credit: US Preventive Services Task Force

A new recommendation statement from the US Preventive Services Task Force (USPSTF) determined the current evidence is insufficient to evaluate the benefits and harms of screening and routine iron supplementation for iron deficiency and iron deficiency anemia during pregnancy to prevent adverse maternal and infant health outcomes.¹

These Grade I statement recommendations apply to asymptomatic pregnant adolescents and adults but do not apply to those who are severely malnourished, have symptoms of iron deficiency or anemia, or have specific hematologic conditions or nutritional deficiencies that may increase the need for iron intake.

“This recommendation is consistent with the 2015 recommendation statement on screening and supplementation for iron deficiency anemia in pregnancy,” wrote Wanda K. Nicholson, MD, MPH, MBA, Milken Institute of Public Health, George Washington University. “In 2015, the USPSTF concluded that the current evidence was insufficient to assess the balance of benefits and harms of screening for iron deficiency anemia in pregnant women to prevent adverse maternal health and birth outcomes (I statement).”

Iron deficiency is the primary cause of anemia during pregnancy. Routine screening or iron supplementation during pregnancy is applied to improve maternal and infant health outcomes. Based on National Health and Nutrition Examination Survey (NHANES) data from 1999–2006, iron deficiency during pregnancy is near 18% prevalence, with notable increases across the 3 trimesters.²

Approximately 5% of pregnant individuals are believed to have iron deficiency anemia. Notably in the US, the prevalence of iron deficiency anemia is disparate across racial, ethnic, and social factors, including socioeconomic status, nutritional status, and food insecurity.

To update the 2015 review on iron deficiency anemia during pregnancy, a search was performed in the Ovid MEDLINE and Cochrane databases through May 2023 and surveillance through May 2024.³ Randomized clinical trials of iron supplementation, screening effectiveness, treatment, and harms were selected for analysis.

The systematic review included 17 trials (n = 24,023) on maternal iron supplementation. These data showed iron supplementation was linked to a lower risk of maternal iron deficiency anemia and iron deficiency at term, compared with placebo or no iron supplementation.

However, maternal iron supplementation led to no statistically significant differences in maternal quality of life, gestational diabetes, maternal hemorrhage, hypertensive disorders of pregnancy, cesarean delivery, preterm birth, infant low birth weight, or infants small for gestational age, compared with placebo or no supplementation.

Overall, no studies addressed the benefit or harm of screening for iron deficiency or iron deficiency anemia during pregnancy. Thus, the recommendation statement determined insufficient evidence to recommend for or against screening or supplementation and called for further research to prevent adverse maternal and infant health outcomes.

Citing these inadequacies in evidence, the USPSTF urged clinicians to use their clinical judgment when screening for iron deficiency and anemia or providing routine iron supplementation during pregnancy.¹ Clinical practice guidelines on screening and supplementation vary but are commonly recommended for this patient population.

The USPSTF has previously released recommendations on screening for iron deficiency anemia in children aged 6 to 24 months, and folic acid supplementation to prevent neural tube defects in individuals who plan to or could become pregnant.

“Having enough iron is important for the health of pregnant people and their babies,” said Esa Davis, MD, MPH, University of Maryland School of Medicine.⁴ “However, we don’t have the evidence we need to determine whether or not screening for iron levels or using iron supplements improve health, so we are calling for more research on both these important topics.”

In an accompanying editorial, Catherine Y. Spong, MD, department of obstetrics and gynecology, UT Southwestern Medical Center, indicated the lack of data on the utility of screening and supplementation for iron deficiency anemia may be secondary to knowledge gaps on health-related social needs influencing the development of iron deficiency.⁵

“The need for rigorous RCTs that are resource-intensive to conduct to answer basic questions about the benign clinical practices of screening and supplementation must be balanced with the need to better understand what factors place patients at risk for iron deficiency anemia in pregnancy,” Spong wrote.

References

1. _{US Preventive Services Task Force. Screening and Supplementation for Iron Deficiency and Iron Deficiency Anemia During Pregnancy: US Preventive Services Task Force Recommendation Statement. JAMA. Published online August 20, 2024. doi:10.1001/jama.2024.15196}
2. _{Mei Z, Cogswell ME, Looker AC, et al. Assessment of iron status in US pregnant women from the National Health and Nutrition Examination Survey (NHANES), 1999-2006. Am J Clin Nutr. 2011;93(6):1312-1320. doi:10.3945/ajcn.110.007195}
3. _{Cantor AG, Holmes R, Bougatsos C, Atchison C, DeLoughery T, Chou R. Screening and Supplementation for Iron Deficiency and Iron Deficiency Anemia During Pregnancy: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force. JAMA. Published online August 20, 2024. doi:10.1001/jama.2024.13546}
4. _{U.S. Preventive Services Task Force Issues Final Recommendation Statement on Screening and Supplementation for Iron Deficiency During Pregnancy. August 20, 2024. Accessed August 20, 2024. https://www.uspreventiveservicestaskforce.org/uspstf/sites/default/files/file/supporting_documents/iron-deficiency-anemia-screening-pregnancy-draft-rec-news-bulletin.pdf}
5. _{Duryea EL, Spong CY. Anemic Data for Preventive Screening and Supplementation to Address Iron Deficiency Anemia in Pregnancy. JAMA. Published online August 20, 2024. doi:10.1001/jama.2024.13545}