title: Progestogen safety: implications for meta-analysis.
authors.forename: J M
authors.initials: JM
authors.lastname: O'Brien
mesh_terms: D005260:Female; D006801:Humans; D011247:Pregnancy; D047928:Premature Birth / Q000517:prevention & control*; D011374:Progesterone / Q000627:therapeutic use*
chemical_list: D011374:Progesterone