title: Study subject to unmeasured confounders and biases.
authors.forename: Anne
authors.initials: A
authors.lastname: Szarewski
authors.forename: Diana
authors.initials: D
authors.lastname: Mansour
mesh_terms: D000736:Androstenes / Q000009:adverse effects*; D003277:Contraceptives, Oral, Combined / Q000009:adverse effects*; D005260:Female; D006801:Humans; D016912:Levonorgestrel / Q000009:adverse effects*; D054556:Venous Thromboembolism / Q000139:chemically induced*
chemical_list: D000736:Androstenes; D003277:Contraceptives, Oral, Combined; D016912:Levonorgestrel