Evidence for a 'healthy pregnant woman effect' in Niakhar, Senegal?

BACKGROUND: Although it is generally believed that pregnancy exposes women to a wide variety of excess health risks that go beyond the direct obstetric complications of pregnancy, the epidemiological evidence in support of such excess indirect risks is inconclusive. In this article we attempt to document the contribution of indirect causes of death to maternal mortality in rural Senegal by using an epidemiological approach whereby the time spent during pregnancy and postpartum is considered a transient period of exposure to the health hazards of childbearing. METHODS: We use data from an ongoing demographic surveillance system in Niakhar, Senegal and calculate rate ratios comparing death rates in pregnant or recently pregnant women (exposed) with death rates in other women (unexposed), including and excluding direct obstetric deaths. RESULTS: Between ages 20 and 44, pregnancy does not confer additional risks to women. After excluding direct obstetric deaths, exposed women aged 20--39 have surprisingly lower risks of death than unexposed women of the same age. For the very young (15-19) and the very old (45-49), on the other hand, the excess risks associated with pregnancy are considerable and, among women age 45 or older, persist even after excluding direct obstetric deaths. CONCLUSION: The apparent protective effect of pregnancy on women's health that is observed in this study illustrates the paradoxical nature of the concept of indirect causes of maternal mortality, and the difficulties in measuring the risks of death attributable to the pregnancy. Further studies aimed at separating risks attributable to the pregnancy from those that are incidental to the pregnancy are required.