Li J, Ng EHY, Stener-Victorin E, et al. Comparison of acupuncture pretreatment followed by letrozole versus letrozole alone on live birth in anovulatory infertile women with polycystic ovary syndrome: a study protocol for a randomised controlled trial. BMJ Open 2016;6:e010955. doi: 10.1136/bmjopen-2015-010955
The trial registration number in the abstract is incorrect, although it is correct in the rest of the article. The Trial registration number in the Abstract should read: NCT02491320 (https://www.clinicaltrials.gov/ct2/results?term=NCT02491320&Search=Search).