TOPLINE:

Pregnant women with iron deficiency without anemia in the first trimester often developed iron deficiency anemia before delivery, although most delivery and newborn outcomes did not differ from those of women with sufficient iron levels and no anemia.

METHODOLOGY:

• Researchers conducted a prospective cohort study to determine whether iron deficiency without anemia in the first trimester was associated with the risk for iron deficiency anemia before childbirth.
• They included 511 women pregnant with a single fetus who received prenatal care at US clinics between February 2023 and July 2025; most women were younger than 35 years.
• Iron deficiency without anemia was defined as ferritin levels < 30 ng/mL with hemoglobin levels ≥ 11 g/dL.
• The primary outcome was iron deficiency anemia before childbirth, defined as receiving a prescription for either oral or intravenous iron therapy during pregnancy or progression to iron deficiency anemia before delivery.

TAKEAWAY:

• Overall, 25% of women had iron deficiency without anemia in the first trimester, and 66% had sufficient iron without anemia.
• A greater proportion of women with iron deficiency without anemia developed iron deficiency anemia before childbirth than those with sufficient iron without anemia (67% vs 35%; P < .001), corresponding to a 91% greater risk (adjusted relative risk [RR], 1.91; 95% CI, 1.57-2.31).
• Women with iron deficiency without anemia in the first trimester had a higher risk for anemia during delivery hospitalization (adjusted RR, 1.62; 95% CI, 1.09-2.42).
• Rates of blood transfusion at delivery, different modes of delivery, preterm birth, admission to the neonatal ICU, and positive screening for postpartum depression, and the median infant birth weight were similar between groups.

IN PRACTICE:

“[The study] findings suggest that identifying IDWA [iron deficiency without anemia] in the first trimester provides an opportunity to prevent overt IDA [iron deficiency anemia] and potential downstream perinatal morbidity,” the researchers of the study wrote.

SOURCE:

The study was led by Nicole Konecke of Brown University in Providence, Rhode Island. It was published online on March 19 as a research letter in American Journal of Obstetrics and Gynecology.

LIMITATIONS:

Researchers excluded women who were screened for iron deficiency after the first trimester. The study was conducted in the US, limiting generalizability. The outcomes were not compared by severity of anemia.

DISCLOSURES:

Five authors reported receiving support from the National Institute of Child Health and Human Development, National Institute on Drug Abuse, and/or National Center for Complementary and Integrative Health. One author reported serving as a paid consultant for Sonio AI and another for placenta AI. 

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.