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. In total, 159 patients were recruited to the study
3 were excluded and 144 of whom tested for aPLs. Among these, 126 (87.5%) were available for diagnostic analysis of antiphospholipid syndrome, 13 (10.3%) of which carried a diagnosis of antiphospholipid syndrome. Meanwhile, 136 of 156 patients had fetal samples for which copy number variation sequencing was completed, and 12 (8.8%) of which carried a diagnosis of fetal chromosomal abnormalities. During later follow-up, among the 13 patients with antiphospholipid syndrome, seven were persistently positive serostatus of antiphospholipid antibodies, four exhibited fluctuation, and one had negative conversion
four patients with subsequent pregnancies received guideline-based therapy and had term livebirths. None of the participants experienced thrombotic events. Maternal antiphospholipid syndrome was found to be one of the important causes of fetal death, contributing 10.3% of cases of fetal death at ≥ 10 weeks of gestation, slight ahead of fetal chromosomal abnormalities. Follow-up indicated that the serostatus of antiphospholipid antibodies may fluctuate significantly in some patients with antiphospholipid syndrome.Clinical trial registration:As this study was an observational study, we did not register it as a clinical trial.