Methodologic considerations for population-based research on fetal deaths: overcoming data gaps.

Fetal deaths comprise a large component of perinatal mortality and remain an understudied pregnancy outcome, especially from a population perspective. Interpretation of the findings from clinical or community-based studies can be difficult without a clear understanding of fetal death at the population level. This article addresses the critical data gaps underlying population-based research on fetal deaths, including the magnitude and scope of the problem, the probability of occurrence, the populations at risk, and the importance of accounting for prior reproductive history. Suggestions are given for new avenues of population-based research such as prospective inquiry of couples attempting pregnancy and newer analytic and modeling strategies for assessing risk and for addressing the lack of independence in pregnancy outcomes.