Related Experiment Video
Updated: Mar 24, 2026

A Clinical Trial Assessing the Safety, Efficacy, and Delivery of Olive-Oil-Based Three-Chamber Bags for Parenteral Nutrition
Published on: September 20, 2019
Utilization of Clinical Trials Registries in Obstetrics and Gynecology Systematic Reviews
Michael E Bibens1, A Benjamin Chong, Matt Vassar
1Oklahoma State University Center for Health Sciences, Tulsa, Oklahoma.
Objective:
To evaluate the use of clinical trials registries in published obstetrics and gynecologic systematic reviews and meta-analyses.
Methods:
We performed a metaepidemiologic study of systematic reviews between January 1, 2007, and December 31, 2015, from six obstetric and gynecologic journals (Obstetrics & Gynecology, Obstetrical & Gynecological Survey, Human Reproduction Update, Gynecologic Oncology, British Journal of Obstetrics and Gynaecology, and American Journal of Obstetrics & Gynecology). All systematic reviews included after exclusions were independently reviewed to determine whether clinical trials registries had been included as part of the search process. Studies that reported using a trials registry were further examined to determine whether trial data were included in the analysis of these systematic reviews.
Results:
Our initial search resulted in 292 articles, which was narrowed to 256 after exclusions. Of the 256 systematic reviews meeting our selection criteria, 47 (18.4%) used a clinical trials registry. Eleven of the 47 (23.4%) systematic reviews found unpublished data and two included unpublished data in their results.
Conclusion:
A majority of systematic reviews in clinical obstetrics and gynecology journals do not conduct searches of clinical trials registries or do not make use of data obtained from these searches. Failure to make use of such data may lead to an inaccurate summary of available evidence and may contribute to an overrepresentation of published, statistically significant outcomes.
Related Concept Videos
Clinical Trials
There are four phases in a clinical trial. A phase one...
Clinical Trials: Overview
Types of Biopharmaceutical Studies: Controlled and Non-Controlled Approaches
Non-controlled studies, commonly employed for initial exploration, lack a control group, rendering them susceptible to biases and external influences. In contrast,...
Study Designs in Epidemiology
Observational studies are those where the researcher does not intervene but rather observes natural variations. They include cross-sectional, cohort, and...
Hazard Ratio
For example, in a clinical trial...
Statistical Software for Data Analysis and Clinical Trials

