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Racial and ethnic distribution of US randomized controlled trials in obstetrics: a retrospective review

  • Yuzuru Anzai ORCID logo EMAIL logo , Noel Cercizi , Yifei Wu , Crystal Park , Narvella Sefah , Isabella Gomez , Nicole Yao , Jasmine Gulati , Seoho Lee , W. Spencer McClelland , Teresa Cheon , Maria Teresa Benedetto-Anzai and Francis A. Chervenak



To determine the racial and ethnic compositions of the participants in obstetric randomized controlled trials (RCTs) and compare them to the US general population.


RCTs published in two premier US journals, American Journal of Obstetrics and Gynecology, Obstetrics and Gynecology from January 2010 to April 2020 were analyzed. The racial and ethnic distributions of the study participants were extracted and expressed as percentages for each article. Obstetrics articles were selected and then further divided into subcategories. Statistical analyses were performed on racial and ethnicity representation in each subcategory compared to a US population norm.


Overall, a wide variation of racial and ethnic distribution was noted among studies. However, statistically significant overrepresentation of Non-Hispanic Black population and underrepresentation of White and Asian races were noted while Hispanic population’s representation was comparable to the US general population. This observation was persistent across most of the subcategories.


RCTs in the field of Obstetrics showed an overrepresentation of Black population. This observation was unique when we consider the previous reports in other fields of medicine. These findings should be taken into consideration when interpreting the results of RCTs conducted in US.

Corresponding author: Yuzuru Anzai, MD, Department of Obstetrics and Gynecology, Lenox Hill Hospital/Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, New York, NY, USA, E-mail:

  1. Research funding: None declared.

  2. Author contributions: All authors have accepted responsibility for the entire content of this manuscript and approved its submission.

  3. Competing interests: Authors state no conflict of interest.

  4. Informed consent: Not applicable.

  5. Ethical approval: Not applicable.


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Received: 2022-02-12
Accepted: 2022-04-07
Published Online: 2022-05-17
Published in Print: 2022-10-26

© 2022 Walter de Gruyter GmbH, Berlin/Boston

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