Standardizing abortion research outcomes (STAR): a protocol for developing, disseminating and implementing a core outcome set for medical and surgical abortion

Approximately one in four of all pregnancies will end in induced abortion with an estimated 56 million taking place worldwide every year [1]. Medical and surgical abortions have low complication rates; however, due to the ubiquity of abortion and the potential for complications if performed unsafely or inappropriately, the need for robust clinical trials and sound guidelines and recommendations is clear [1,2]. Besides the recent release of the Medical Abortion Reporting of Efficacy guidelines, there is a lack of standardized methods for selecting and reporting on outcomes in abortion clinical trials [3].