This study investigates the short-term impact on the quantity and quality of births of an abortion reform in Uruguay that legalised termination of pregnancy until the 12 week of pregnancy in the short run. We employ a differences-in-differences approach, comprehensive administrative records of births, and a novel identification strategy based on the planned or unplanned nature of pregnancies that came to term. Our results suggest that this policy change has led to an 8% decline in the number of births from unplanned pregnancies, driven by the group of mothers aged between 20 and 34 years old who have secondary education. This decline has triggered an increase in the average quality of births in terms of more intensive prenatal control care and a lower probability of births among single mothers. Furthermore, we document a positive selection process of births because of the reform, as adequate prenatal control care and Apgar scores rose among the affected demographic group.