Characteristics and Publication Patterns of Obstetric Studies Registered in Clinicaltrials.gov

<p> 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 <a href="http://clinicaltrials.gov/"> ClinicalTrials.gov </a> from 2007 to 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 <a href="http://clinicaltrials.gov/"> ClinicalTrials.gov </a> . Of 93,709 total studies, there were 5,203 (6%) obstetric studies registered in <a href="http://clinicaltrials.gov/"> ClinicalTrials.gov </a> . 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 2 years ago, only 11% had reported results and &lt;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&hyphen;quality trial design is concerning. The sources of this trend should be closely investigated.</p>