Several recent papers have dealt with the problem of assessing the impact of the proximate determinants on fertility. All these approaches rely on combining a series of separately estimated aggregate level indicators. This paper proposes an approach which uses individual-level data and thus permits regression analyses as well as analyses for sub-groups. In the course of development it became clear that there are several deficiencies and inconsistencies in the measurement and formation of indices proposed elsewhere, which are overcome. We illustrate our approach with data from the Dominican Republic. The approach used involves attributing exposure to one or more of several states, including pregnancy. lactational and non-lactational components of post-partum amenorrhoea, absence of sexual relations and contraception. Key elements are efficacies of contraception and components of post-partum infecundity and the treatment of overlaps through an explicit hierarchy. We treat both unconditional (or additive) and conditional analyses. Intriguing findings on the age-specific pattern of fertility control emerge. Major advantages of regression analysis, such as simultaneous treatment of several variables and estimation of sampling variation are stressed.