Collecting data on pregnancy loss: a review of evidence from the World Fertility Survey.

Estimates of levels and differentials of pregnancy loss are presented for 40 developing countries participating in the World Fertility Survey (WFS) program. Judged against agreed-upon levels of spontaneous loss in human populations, WFS surveys measured from 50 to 80 percent of recognizable losses. The coverage of induced abortions appears to be much worse. Consistent with data from other sources and settings, the probability of loss is strongly correlated with maternal demographic characteristics: age, pregnancy order, pregnancy spacing, and pregnancy loss history. Despite incomplete coverage, the WFS data on pregnancy loss provide considerable, and largely unexploited, insight on the dynamics of the reproductive career.