Deaths attributable to childbearing in Matlab, Bangladesh: indirect causes of maternal mortality questioned.

Little is known about the nature of diseases aggravated by pregnancy or the magnitude of mortality from causes indirectly related to pregnancy. This study aims at clarifying the contribution of indirect causes to maternal mortality by analyzing the problem from an epidemiologic perspective, using population-based data from Matlab, Bangladesh, for the period 1976-1993. The time spent during pregnancy and the puerperium was considered a transitory exposure period in women's lives, and death rates were calculated for women aged 15-44 years, while exposed and while not exposed. During or shortly after pregnancy, death rates from all causes are more than twice as high as outside this period. Once direct obstetric causes and injuries are excluded, the death rates among women while exposed are substantially lower than the death rates among women while not exposed. Several interpretations of this finding are discussed, particularly the role of selective factors ("healthy pregnant woman effect"?). This study highlights the complexity of the concept of indirect causes of maternal mortality and clearly illustrates the inherent difficulties in estimating the excess risk of death attached to pregnancy and the puerperium.