This study analyzes the impact that publishing during the period of PhD study has on researchers' future knowledge production, impact, and co-authorship. The analysis is based on a representative sample of PhDs from all fields of science working in Portugal. For each researcher in the dataset, we compiled a lifetime publication record and respective meta-data retrieved from Thomson Reuters Web of Science. Our results extend the previous literature by showing that those who publish during their PhD have greater research production and productivity, and greater numbers of yearly citations and citations throughout their career compared to those who did not publish during their PhD. Moreover, it is found that those who publish during their PhD are more adept to publish single-authored publications and engage in publications with peers based abroad, thus suggesting both higher levels of scientific autonomy and international collaboration dynamics.