TOPLINE:

The prevalence of anemia increased from around 4% at prenatal care initiation to over 20% by mid-pregnancy.

METHODOLOGY:

• Researchers evaluated the prevalence of anemia and trends during pregnancy using data from a claims database of commercially insured patients from 2018 to 2023.
• Around 65,528 pregnancies were included, with participants having singleton live births or stillbirths at 28 weeks of gestation or later and no diagnosis of hereditary anemia.
• Participants had hemoglobin and hematocrit values measured during routine screening periods during the first trimester and between 22 weeks and 30 weeks of gestation.
• Anemia was defined as a hemoglobin level < 11 g/dL or a hematocrit level < 33% in the first and third trimesters, and as a hemoglobin level < 10.5 g/dL or a hematocrit level < 32% in the second trimester.

TAKEAWAY:

• Overall, the prevalence of anemia during pregnancy was 25.6%.
• Cross-sectional analysis by trimester revealed an anemia prevalence of 4.5% in the first trimester, 20.2% in the second trimester, and 36.2% in the third trimester.
• The prevalence of anemia in the study was more than double of estimates in the National Health and Nutrition Examination Survey of 2.7%, 2.2%, and 10.8% in the first, second, and third trimesters, respectively.

IN PRACTICE:

“[The study findings underscore] the need for effective approaches to treat preexisting anemia, including the precursor iron deficiency, and prevent the development of anemia as pregnancy progresses,” the authors of the study wrote.

SOURCE:

The study was led by Irogue I. Igbinosa, MD, MS, Division of Maternal-Fetal Medicine and Obstetrics, Stanford University School of Medicine, Palo Alto, California. It was published online on March 26, 2026, as a research letter in Obstetrics & Gynecology.

LIMITATIONS:

The laboratory measurements to determine anemia on admission were not available. Ferritin values were not routinely measured, preventing the classification of anemia types. Differences in anemia prevalence by race and ethnicity and structural determinants of health could not be examined.

DISCLOSURES:

The study received support from the National Center for Advancing Translational Sciences Clinical and Translational Science Award and from the Eunice Kennedy Shriver National Institute of Child Health and Human Development. One author disclosed serving as a consultant for Bloomlife and holding stock in Zenflow.

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