['Little is known about pregnancy rates among sex workers (SWs) or the factors that predispose SWs to this risk. We aimed to estimate the pregnancy incidence rate among Madagascar SWs participating in an intervention trial promoting use of male and female condoms and assess the influence of various predictive factors on pregnancy risk.', 'SWs from two study clinics in Madagascar participated in a randomized trial to assess the effect of peer education and clinic-based counseling on use of male and female condoms and prevalence of sexually transmitted infections (STIs). Women were seen every 2 months for up to 18 months; they received structured interviews at every visit, and physical exams at baseline and every 6 months thereafter. Site staff recorded information on pregnancies during interviews; pregnancy data were then merged with trial data for this analysis.', 'Of 935 SWs in the analysis population, 250 became pregnant during follow-up. The cumulative probability of pregnancy was 0.149 at 6 months and 0.227 at 12 months. Comparable proportions of nonpregnant and pregnant SWs reported using highly effective contraception at baseline (approximately 16%); these users were younger and were more consistent condom users. Method switching and discontinuation were frequent. In multivariate analysis, nonuse of effective contraceptives and any self-reported unprotected sex were associated with higher incidence of pregnancy. Approximately 51% of women delivered, 13% reported a spontaneous abortion, 13% reported an induced abortion and 23% had missing pregnancy outcomes.'] Does pregnancy among sex workers participating in a condom intervention trial highlight the need for dual protection?