Epidemiological issues in perinatal outcomes research.

Outcomes research takes an expansive view of health and seeks to improve the science of evaluating the quality of health care by refining traditional clinical measures and including measures of overall patient well-being. This broader view of health (rather than disease) is especially appropriate in perinatal research. Attention to the perinatal period requires recognition that pregnancy is in most cases a healthy life event, that there is a predictable progression and time course with a key definable outcome (delivery) and that there are two patients, mother and infant. Two issues stand out as methodological challenges in the design and conduct of perinatal outcomes studies. The first is to establish baseline comparability across study groups with regard to case-mix or perinatal risk, and also comparability of services other than the one under study. The second is the refinement of traditional perinatal outcomes, such as low birthweight and Caesarean section, and the inclusion of patient-based health status measures, such as health-related quality of life, for the peripartum woman and her newborn.