Characteristics and publication patterns of obstetric studies registered in ClinicalTrials.gov

Abstract

Physiologic changes during pregnancy alter the pharmacokinetics, safety, and efficacy of many drugs. For clinicians, there is often uncertainty regarding the safety of these drugs due to a scarcity of published data. This study aimed to comprehensively evaluate the characteristics and publication patterns of obstetric studies registered in ClinicalTrials.gov from 2007-2012. Primary outcome measures, funding sources, inclusion criteria, and the reporting of study results were evaluated. A manual review of Medline/PubMed was performed to identify publications associated with studies registered in ClinicalTrials.gov. Of 93,709 total studies, there were 5,203 (6%) obstetric studies registered in ClinicalTrials.gov. Interventional studies accounted for 70% and 30% were observational. Clinical trials of drugs (49%), procedures (13%), and behavioral interventions (12%) were most common. Among interventional drug trials, 84% featured randomized allocation to study arms and 93% included measures of safety and/or efficacy as primary endpoints. Of 946 (18%) studies completed more than two years ago, only 11% had reported results and less than 7% had been published. In an area with a great need for evidence of safe and effective therapies, the low publication rate of completed studies incorporating elements of high-quality trial design is concerning. The sources of this trend should be closely investigated.

A Review of Ginseng Clinical Trials Registered in the WHO International Clinical Trials Registry Platform

“…Another positive finding is that a comparatively large proportion of finished GCTs have already been published in peer-reviewed biomedical journals. Our observed publication rate (71%) of registered GCTs is higher than the rates observed in other clinical trials [ 11 , 23 – 26 ]. Reasons for failure to publish include lack of positive results, time restriction, limited resources, change of interests, or simply failure to have the paper accepted by a journal [ 26 ].…”

Inclusion of pregnant and breastfeeding women in research – efforts and initiatives

“…The study by Stockmann et al . examined the characteristics of obstetric studies registered within http://clinicaltrials.gov from 2007 to 2012, demonstrating that these studies represented less than 10% of the total number registered. The authors also found that more than 80% of obstetric studies registered from 2007 to 2012 incorporated elements of high‐quality trial design (e.g.…”

Are citations from clinical trials evidence of higher impact research? An analysis of ClinicalTrials.gov

“…Moreover, some journals require published studies to have been preregistered in an appropriate site (Laine, Horton, DeAngelis, et al, 2007;Palma, & Zietman, 2015). ClinicalTrials.gov contains information about a large number of public and commercial trials (Califf, Zarin, Kramer, Sherman, Aberle, & Tasneem, 2012;Hirsch, Califf, Cheng, et al, 2013;Ross, Mulvey, Hines, Nissen, & Krumholz, 2009;Stockmann, Sherwin, Koren, et al, 2014;Zarin, Tse, & Ide, 2005;Zarin, Tse, Williams, Califf, & Ide, 2011) and so it is now possible to count citations from clinical trials records. These citations can therefore be evaluated as a new source of evidence about the health benefits promise of medical research.…”