How often is the placenta included in human pregnancy research? A rapid systematic review of the literature

Abstract Background: The placenta is a complex organ that plays a vital role not only in nutrient transfer but also in directing maternal and fetal physiological processes across pregnancy. Due to its multi-functionality, assessing the placenta can provide critical information about maternal and child health and risks of adverse outcomes. Objective: We aimed to quantify the percentage of human pregnancy studies that include placenta data. Methods: We conducted a rapid review of pregnancy studies conducted in the US that were published as original research in PubMed in 2018. Human studies conducted during the second trimester, third trimester, or labor and/or delivery were eligible. The systematic search produced 1,448 publications. After screening and full article review, 290 studies met all eligibility criteria. We then extracted data on study design, reporting of placenta data, time and type of data collection, and study objective categorization. Results: In total, 32% of studies were randomized controlled trials; the remaining were observational studies. Only 14% included placenta data of any kind. A total of 10% included placenta data during pregnancy and 7% included data after delivery; only 2% included both. Most data during pregnancy were collected by ultrasound and most data on the delivered placenta were from pathology exams. Study objectives were focused on maternal and/or infant outcomes (99.7%), while only one study had a placenta outcome. Conclusion: Based on this rapid review, a small proportion of pregnancy studies use placenta data in research. The placenta, an essential component of understanding healthy or adverse outcomes, deserves much more attention in pregnancy research.



Work Title How often is the placenta included in human pregnancy research? A rapid systematic review of the literature
Subtitle Placenta Rapid Review Data Extraction Tool
Open Access
  1. Leigh Taylor
  2. Kelly Gallagher
  3. Katherine Anne Ott
  4. Alison D Gernand
  1. pregnancy
  2. placenta
  3. rapid review
  4. pathology
  5. ultrasound
License CC0 1.0 (Public Domain Dedication)
Work Type Dataset
Publication Date 2021
DOI doi:10.26207/857e-0b73
Deposited February 18, 2021




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Work History

Version 1

  • Created
  • Added Creator Leigh Taylor
  • Added Creator Kelly Gallagher
  • Added Creator Katherine Anne Ott
  • Added Creator Alison D Gernand
  • Added Placenta Rapid Review Data Extraction_ScholarSphere.xlsx
  • Updated Subtitle, License Show Changes
    • Data Extraction Tool
    • Placenta Rapid Review Data Extraction Tool
  • Published
  • Updated