While little is known about how a medicalised birth influences developing infant temperament, high-impact interventions that affect neonatal crying and cortisol levels may have long-term consequences for baby behaviour and functioning. Additionally, the mother’s psychological wellbeing during and after birth could influence outcomes. The study presented over the next two chapters used an online survey to examine the relationship between physical and psychological childbirth experiences, mothers’ perceptions of their babies’ behavioural style (known as temperament) and their confidence and self-efficacy in caring for their babies. Although both physical (objective) and psychological (subjective) factors were linked to the newborn baby’s initial response, it was the mother’s subjective states during childbirth and the perinatal period that were most significantly associated with early infant temperament. For example, experiencing anxiety and fear during childbirth and postnatal depression were linked to more unsettled infants who were more likely to have irregular routines in feeding, sleeping and elimination. Conversely, mothers were more likely to report that their baby was alert and responsive and displayed overall easier behaviour following a well-supported birth experience. Mothers’ confidence and self-efficacy were also related to both physical and psychological aspects of the birth experience, as well as to baby behaviour. Strong emotional support during childbirth was highly valued, as it significantly enhanced the birth experience and appeared to improve outcomes for both mother and baby.