Abstract
OBJECTIVE
This study aimed to evaluate the outcomes among individuals who were eligible and
approached for participation in a randomized controlled trial during pregnancy, comparing
those who enrolled with those who declined participation.
DATA SOURCES
MEDLINE, Scopus, CINAHL, the Cochrane Library, and Ovid were searched from study inception
to May 2022.
STUDY ELIGIBILITY CRITERIA
This study included all obstetrical randomized controlled trials that reported clinical
outcomes for both participants and nonparticipants.
METHODS
The primary outcome captured the presence of morbidity. It was a composite of the
primary outcome of each study comparing the participant arm with the nonparticipant
arm. If a primary outcome was not clearly defined, a surrogate was developed on the
basis of the core outcomes for the clinical condition studied. The risk of bias was
assessed with the Newcastle-Ottawa Scale. Subgroup analyses for relevant obstetrical
and neonatal outcomes were performed. The summary comparisons were reported as odds
ratios with 95% confidence intervals computed using random-effects meta-analysis with
heterogeneity evaluated using the I2 statistic. A funnel plot was used to examine publication bias, and there was no asymmetry.
RESULTS
After reviewing more than 1100 abstracts, 17 obstetrical randomized controlled trials
(103,610, with 26,293 participants and 77,317 nonparticipants) met our inclusion criteria
and were analyzed. Of note, 9 studies were not rated as high quality, primarily for
failing to control for confounding factors. Trial interventions were categorized as
antepartum (n=11), intrapartum (n=5), or postpartum (n=1). Overall, participants in
obstetrical randomized controlled trials had no difference in outcomes compared with
nonparticipants (n=17: odds ratio, 0.88; 95% confidence interval, 0.52–1.49; I2=90%). Moreover, there was no difference seen when only randomized controlled trials
that reported a primary outcome were included (n=12: odds ratio, 0.76; 95% confidence
interval, 0.38–0.1.49; I2=93%). In addition, there was no difference noted in the subgroup where the randomized
controlled trial intervention was not available to nonparticipants (n=7: odds ratio,
0.91; 95% confidence interval, 0.45–1.85; I2=68%).
CONCLUSION
Pregnant individuals who agreed to participate in randomized controlled trials had
no difference in outcomes compared with those who decline participation. Pregnant
individuals should be provided with this reassuring information when offered to participate
in a randomized controlled trial. Moreover, this information may improve patient recruitment
into randomized controlled trials.
Key words
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Article info
Publication history
Published online: July 15, 2022
Accepted:
July 7,
2022
Received:
July 2,
2022
Footnotes
The authors report no conflict of interest.
This study received no financial support.
This study was registered with the International Prospective Register of Systematic Reviews (registration number: CRD42021233077) on March 6, 2021.
This study was presented at the 2022 Society for Maternal-Fetal Medicine Annual Pregnancy Meeting, held virtually, January 31, 2022, to February 5, 2022.
K.S.K. is a distinguished investigator supported by the Beatriz Galindo (senior modality) Program grant given to the University of Granada by the Ministry of Science, Innovation and Universities of the Spanish Government.
All authors have completed the International Committee of Medical Journal Editors uniform disclosure form at http://www.icmje.org/coi_disclosure.pdf and declare no support from any organization for the submitted work, no financial relationship with any organizations that might have an interest in the submitted work in the previous 3 years, and no other relationships or activities that could seem to have influenced the submitted work.
The lead author (the manuscript's guarantor) affirms that the manuscript is an honest, accurate, and transparent account of the study being reported, that no important aspect of the study has been omitted, and that any discrepancies from the study as planned have been explained.
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