Much of the inconsistency that has appeared in studies of the effect of women's work on fertility in less developed countries has been attributed to the varying accessibility of employment in the modern sector. The analysis presented in this paper shows that continuity of work matters more than sector of work. It also confirms that, even in a setting of low contraceptive prevalence, increased fecundity associated with the less intense breastfeeding practices of working women do not result in shorter birth intervals. The influence of women's work on fertility control is likely to be underestimated if the effects of sporadic versus continuous work are conflated, or if fecundity differentials by work status are unmeasured.