A natural timescale for studying the effect of labour on the survival of a cohort is the age of gestation measured in weeks since the last menses of the mother. Unlike chronological age, the gestational time scale allows for existence before infancy, thereby making it possible to study birth as a transition. On the aggregate level, this transition appears as a “hump” in an otherwise exponentially declining hazard of death for a cohort of fetuses as we follow them on their way into life. In this talk, Jonas will discuss his research studying this gestational age pattern across multiple populations with a particular focus on describing the phenomenon of the “birth hump” – the excess risk of death associated with the transition of birth.