We searched several databases (all from inception to March 31, 2009) with the terms
“amniotic embolism” and “amniotic embolus”. We also searched references in retrieved
articles, book chapters, review articles, and reports on maternal mortality from surveillance
systems. Inclusion of individual articles was based on scientific merit and clinical relevance.
The great majority of studies included were descriptive, mainly case reports and case series.
We also included 2 population-based cohort studies and 6 case-control studies.
Methodological quality was assessed using guidelines proposed for improving the reporting
of these studies.4,5 Details of methods used in the review are presented in the Appendix.