Abstract: A retrospective observational study was conducted to evaluate open-access journals in obstetrics and gynaecology, published between 2011 and 2019. Journals were classified based on their registration in open-access journal directories. Of 176 journals, 47 were not registered. Journals registered in the Directory of Open Access Journals (DOAJ) demonstrated good overall quality, and their journal metrics were significantly higher than those of non-registered journals or journals registered in other directories. The lack of editor names and indexing information on a journal’s website are the most distinctive features of non-registered journals. Non-registration in an open-access journal directory indicates a lack of transparency and may ultimately indicate that a journal is predatory.