Women represent the majority of informal workers in developing countries, especially in Sub-Saharan Africa. It is also the case that the region is characterised by high adolescent pregnancy rates. Little empirical evidence exists concerning the causal relationship between teen fertility and the likelihood of informal employment. Using longitudinal data from Madagascar designed to capture the transition from adolescence to adulthood, we estimate a multinomial logit model to capture the effect of the timing of first birth on female selection into four categories: non-participation, informal employment, formal employment, and student. To address the endogeneity of fertility and labor market outcomes, we instrument timing of first birth using women’s community-level access, and duration of exposure to family planning. Our results suggest that motherhood increases the probability of employment and that women whose first birth occurs during adolescence are mostly employed into low-quality informal jobs. This effect is partially, but not entirely, mediated by the effect of teen childbearing on schooling.