PREDICTORS OF FECUNDABILITY AND CONCEPTION WAITS AMONG THE DOGON OF MALI

Surprisingly little is known about the mechanisms that underlie variat ion in female fertility in humans. Data on this topic are nonetheless vital to a number of pragmatic and theoretical enterprises, including population planning, infertility treatment and prevention, and evoluti onary ecology. Here we study female fertility by focusing on one compo nent of the interbirth interval: the waiting time to conception during menstrual cycling. Our study population is a Dogon village of 460 peo ple in Mall, West Africa. This population is pronatalist and noncontra cepting. In accordance with animist beliefs, the women spend five nigh ts sleeping at a menstrual hut during menses. By censusing the women p resent at the menstrual huts in the study village on each of 736 conse cutive nights, we were able to monitor women's conception waits prospe ctively. Hormonal profiles confirm the accuracy of the data on concept ion waits obtained from the menstrual hut census (Strassmann [1996], B ehavioral Ecology 7:304 - 315). Using survival analysis, we identified significant predictors of the waiting time to conception: wife's age (years), husband's age (< 35, 35 - 49, > 49 years), marital duration ( years), gravidity (number of prior pregnancies), and breast-feeding st atus. Additional variables were not significant, including duration of postpartum amenorrhea, sex of the last child: nutritional status, eco nomic status, polygyny, and marital status (fiancee vs. married). We f it both continuous and discrete time survival models, but the former a ppeared to be a better choice for these data. (C) 1998 Wiley-Liss, Inc .