Antiphospholipid syndrome in patients with fetal death: a prospective longitudinal cohort study.

To investigate the causes of fetal death, focusing on maternal antiphospholipid syndrome diagnosis, and to follow the patients for changes in antiphospholipid antibodies, subsequent pregnancy outcomes, and thrombotic events. This is a prospective longitudinal cohort study that recruited patients who were hospitalized for fetal death at ≥ 10 weeks of gestation from three tertiary hospitals in China. Antiphospholipid syndrome was diagnosed according to the 2006 Sydney classification criteria.