Developing a core outcome set in interventions to prevent stillbirth: A systematic review on variations of outcome reporting

To determine which outcomes have been previously reported in previous stillbirth prevention studies. Systematic review of reviews: We searched the Cochrane Database of Systematic Reviews, EMBASE and Pubmed for systematic reviews and meta- analyses investigating interventions to prevent stillbirth and its major risk factors. Data collection and analysis: Two reviewers identified and extracted outcomes independently. Outcomes were categorised under relevant domains for analysis. Frequency of each outcome was also determined. From 51 eligible reviews, 16 reviews addressed stillbirth prevention specifically while 35 reviews evaluated the efficacies of prevention or management of the eight major risk factors of stillbirth. Two hundred and thirty-seven outcomes were extracted, including 150 maternal outcomes and 87 offspring outcomes. Stillbirth (35/51), perinatal mortality (34/51) and neonatal mortality (33/51) were the most commonly reported outcomes followed by birthweight (29/51), caesarean section (28/51) and preeclampsia/eclampsia (23/51). Self-reported mother/family focused outcomes on their experiences and views were reported in 10/51 reviews. In studies evaluating prevention of stillbirth there is a large variety in outcomes, with discrepancies in nomenclature and measurements. Woman/family-centred outcomes are often missing from studies. There is a need for a core outcome sets agreed by all stakeholders containing the recommended minimum data to be reported in future studies investigating prevention of stillbirth. •Review of reviews is an efficient synthesis of a broad field of evidence.•There is a possibility that reporting bias from the original systematic reviews were incorporated.•To our knowledge, this is the first attempt to comprehensively assess the current status of outcome reporting in stillbirth prevention studies.•Extraction revealed a wide variability in measurements and inconsistency in outcomes reporting in stillbirth prevention studies.•Future study is required to determine how to measure the outcomes extracted from the current review.•Extraction demonstrated inconsistency in definition and measurement of outcomes in stillbirth prevention studies which can lead to lost opportunities for evidence synthesis from research carried out in the same area.