PPO.10 Recurrence risk of unexplained stillbirth: A systematic review and meta-analysis

Background Stillbirth remains a significant problem worldwide. Unexplained stillbirth is the most common classification of cause of death accounting for between 10–70%. Studies that investigate recurrence risk of unexplained stillbirth yield inconsistent results. Objective To investigate the association between unexplained stillbirth in a first pregnancy and recurrence risk of stillbirth in a subsequent pregnancy in high-income countries. Methods Six databases were searched using a comprehensive search strategy to identify relevant cohort and case-control studies. No publication status, language or date restrictions were applied. Internet resources and reference lists of relevant papers were also searched. Using explicit a priori criteria two reviewers independently screened titles to identify eligible studies, extract data and assess methodological quality. Random-effects meta-analyses were used to combine results of included studies. Results Seventeen studies were included in the systematic review fifteen of which were considered eligible for the meta-analysis. Stillbirth and unexplained stillbirth in a first pregnancy was associated with an increased risk of stillbirth in a subsequent pregnancy. Compared with women who had a live birth in a first pregnancy the pooled crude and adjusted odds ratios (OR) and 95% confidence intervals (CI) of stillbirth recurrence for women with a previous stillbirth were 4.75(3.74, 6.03) and 2.34(1.53, 3.57) respectively. Compared with women who had a live birth in a first pregnancy the pooled adjusted OR of stillbirth recurrence for women with a previous unexplained stillbirth was 1.83(1.38, 2.44) Conclusion This systematic review and meta-analysis provides some evidence to support an increased recurrence risk for unexplained stillbirth.