Recurrence risk of unexplained antepartum stillbirth
METHODS: Using a comprehensive search strategy, six databases Medline, Embase, Cinhal, Scopus, Pubmed and the Cochrane Library were searched systematically with no restrictions applied to identify studies that examined the recurrence risk of unexplained stillbirth. A combination of MeSH terms, text and key words for ‘stillbirth’, ‘recurrence’ and ‘pregnancy’ was used to identify primary studies. Supplementary efforts included searching relevant internet resources, visually scanning the reference lists of relevant studies and contacting authors. Using explicit a priori selection criteria two reviewers independently screened titles to identify eligible studies, extracted data and assessed the methodological quality using critical appraisal skills programme scoring. Random-effects meta-analyses were used to combine the results of included studies. Subgroup analyses was performed on studies examining recurrence risk of unexplained stillbirth
RESULTS: Seventeen studies were included in the systematic review; fifteen of which were included in the meta-analysis. Stillbirth overall and unexplained stillbirth were associated with an increased risk of stillbirth in a subsequent pregnancy. Compared to women with an initial live birth, the pooled unadjusted and adjusted odds ratios (95% confidence intervals) of stillbirth recurrence for women with a previous stillbirth were 4.75(3.74, 6.03) and 2.34(1.53, 3.57) respectively. The pooled risk of recurrence was 1.83(1.38, 2.44) for unexplained stillbirth.
CONCLUSIONS: This systematic review and meta-analysis found an increased recurrence risk of unexplained stillbirth, but this was not as high as that for stillbirth with known causes.