Background
Obstetric complications impact over a third of women globally, but are underrepresented in clinical research. Little is known about the comprehensive obstetric clinical trial landscape, how it compares to other fields, or factors associated with the successful completion of obstetric trials.
Objectives
To characterize obstetric clinical trials registered on
ClinicalTrials.gov
with the primary objective of identifying features associated with early discontinuation and results reporting.
Study Design
This is a cross-sectional study with descriptive, logistic regression and cox regression analyses of clinical trials registered on
ClinicalTrials.gov
. Our primary exposure variables were trial focus (obstetric or non-obstetric) and trial funding (industry, United States government or academic). We conducted additional exploratory analyses of other trial features including design, enrollment, and therapeutic focus. We examined the associations of exposure variables and other trial features with two primary outcomes: early discontinuation and results reporting.
Results
We downloaded data for all studies (n=332,417) registered on
ClinicalTrials.gov
from October 1, 2007 to March 9, 2020 from the Aggregate Analysis of the
ClinicalTrials.gov
database. We excluded studies with a non-interventional design (n=63,697) and those registered before October 1, 2007 (n=45,209). 4,276 (1.9%) obstetric trials (i.e. interventional studies), and 219,235 (98.1%) non-obstetric trials were compared. Among all trials, 2.8% of academic-funded trials, 1.9% of United States government-funded trials, and 0.4% of industry-funded trials focused on obstetrics. The quantity of obstetric trials increased over time (10.8% annual growth rate). Compared to non-obstetric trials, obstetric trials had a greater risk of early discontinuation (adjusted hazard ratio 1.40, 95% confidence interval: 1.21 to 1.62, p<0.0001) and similar odds of results reporting (adjusted odds ratio 0.89, 95% confidence interval: 0.72 to 1.10, p=0.19). Among obstetric trials funders after controlling for confounding variables, United States government-funded trials were at lowest risk of early discontinuation (US government adjusted hazard ratio 0.23, 95% confidence interval 0.07 to 0.69, p=0.009, industry reference; academic adjusted hazard ratio 1.04, 95% confidence interval 0.62 to 1.74, p=0.88). Academic-funded trials had the lowest odds of results reporting after controlling for confounding variables (academic institutions adjusted odds ratio 0.39, 95% confidence interval 0.22 to 0.68, p=0.0009; industry reference; US government adjusted odds ratio 1.06 95% confidence interval 0.53 to 2.09, p=0.87).
Conclusions
Obstetric trials represent only 1.9% of all clinical trials in
ClinicalTrials.gov
and have ...