Obstetrics / Pregnancy / Humans / Fertility and Sterility / Female / Anticoagulants / Clinical Sciences / Gynecology / Public health systems and services research / Pregnancy Rate / Cohort Studies / Factor XI / Recurrent pregnancy loss / Anticoagulants / Clinical Sciences / Gynecology / Public health systems and services research / Pregnancy Rate / Cohort Studies / Factor XI / Recurrent pregnancy loss