We aimed to examine factors associated with early discontinuation and incomplete results reporting in obstetric clinical trials. We performed an exploratory cross sectional and logistic regression analysis of factors associated with early discontinuation and results reporting in obstetric trials registered in Clinicaltrials.gov from October 2007-June 2018 adjusting for trial type, sponsor, design, and therapeutic focus. Between October 2007-June 2018, 277,438 clinical trials were registered on ClinicalTrials.gov. 1.2% of these trials (3317, representing 4,011,806 participants) focused on obstetrics. A total of 239 trials (7.1% of obstetric trials with 23,593 participants), were discontinued early due to termination (135, 56.5%), withdrawal (90, 37.7%), or suspension (14, 5.9%). Of the therapeutic foci, maternal nutrition studies had the lowest (OR 0.51 CI:0.28-0.93) and early delivery the highest (OR 2.18, CI: 1.22-3.92) odds of early discontinuation. Industry trials were the most likely to be stopped early (Industry 12.7%; NIH 0.5%; other 7.1%, Figure 1). Basic science (OR 0.21, CI: 0.06-0.71) and prevention (OR 0.63 CI: 0.42-0.95) trials had lower odds of discontinuation than treatment trials (reference category). In 2016, 1,114 obstetric trials had reached completion, but only 13.4% had reported results by 2018 (Table 1). Industry and NIH trials were more likely to complete result reporting (27.1% and 27.8% respectively) than Other trials (11.1%). Trials with a data monitoring committee and randomization had greater odds of complete results reporting (p< 0.05). This represents a comprehensive analysis of early discontinuation and results reporting in modern obstetric clinical trials. Over 7% of obstetric clinical trials had early discontinuation. Results reporting in obstetric clinical trials was low, despite statues requiring all clinical trials to report results in a timely manner. Identifying factors associated with early discontinuation and results reporting represents a first step towards improving trial completion and dissemination.View Large Image Figure ViewerDownload Hi-res image Download (PPT)