USPSTF reports gaps in evidence for iron deficiency screening in pregnancy

The US Preventive Services Task Force (USPSTF) has current evidence comparing the benefits and risks of iron supplementation and found that iron deficiency anemia screening is insufficient, publishing a recommendation statement in JAMA to recap the current data.¹

Iron deficiency has been estimated in approximately 18% of pregnant women, with 5% developing iron deficiency anemia.² However, the USPSTF has highlighted a lack of significant data to determine the influence of screening for these conditions on maternal and infant health outcomes.¹

“Due to lack of available data, the USPSTF concludes that the current evidence is insufficient, and the balance of benefits and harms of iron supplementation in asymptomatic pregnant persons on maternal and infant health outcomes cannot be determined,” wrote the authors.

Weighing clinical decisions

While these recommendations apply to asymptomatic patients, the authors noted they do not apply to those with severe malnourishment, iron deficiency or iron deficiency anemia symptoms, specific hematologic conditions, or nutritional deficiencies. Iron is vital for oxygen transportation and metabolic pathway function, making supplementation necessary in some patients.

According to the USPSTF, clinicians should consider the potential preventable burden when deciding whether to screen or supplement for iron deficiency. Current methods of identifying risk, such as questionnaires and risk prediction tools, have limited evidence supporting their use based on 3 studies assessing these strategies.

Potential harms should also be considered, as evidence is also limited about any adverse effects of iron deficiency screening among asymptomatic patients. Iron supplementation has been linked to adverse effects such as constipation, nausea, vomiting, and abdominal pain.

Variations in screening and supplementation practices

The USPSTF noted variations in screening and supplementation practices for iron deficiency, though typical use of these tools was identified. This included a first-trimester hemoglobin screening rate of 53% among Special Supplemental Nutrition Program for Women, Infants, and Children participants.

Racial and ethnic disparities have also been reported in screening rates, with reduced odds of receiving a complete blood cell count reported in Asian, Black, and Hispanic Medicaid recipients vs White recipients. ORs for this association ranged from 0.51 to 0.92.

Iron supplementation within the past 30 days has been reported in 77% of pregnant patients recorded in the National Health and Nutrition Examination Survey. However, food insecurity was linked to a reduction in mean iron intake from supplements.

The USPSTF also highlighted resources for obstetric health care, such as state collaborative tool kits from the CDC and a fact sheet about iron by the National Institutes of Health. A fact sheet about iron deficiency anemia has also been published by the US Department of Health and Human Services.

Additional recommendations

Recommendations from other organizations were also included in the statement. Screening for anemia during the first prenatal visit is recommended by multiple organizations, including the CDC, American College of Obstetricians and Gynecologists (ACOG), and American Academy of Family Physicians.

ACOG also recommends repeat screening at 24- to 28-weeks’ gestation. Supplementation guidelines were also highlighted, including recommendations from the CDC that all pregnant patients receive universal supplementation with an oral low-dose iron supplement of 30 mg daily.

ACOG also recommends screening pregnant patients for low-dose iron during pregnancy. Once the cause of low-dose iron is identified, treatment with low-dose supplemental iron should be provided. Overall, these recommendations highlight steps for screening and the supplementation of iron deficiency in pregnancy, despite gaps in evidence.

“The USPSTF continues to call for high-quality research, particularly on the critical gap of the association between changes in maternal iron status and improvement in infant and maternal outcomes in pregnant persons,” wrote statement authors.

References

1. US Preventive Services Task Force; Nicholson WK, Silverstein M, Wong JB, et al. Screening and supplementation for iron deficiency and iron deficiency anemia during pregnancy: US Preventive Services Task Force Recommendation Statement. JAMA. 2024;332(11):906–913. 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