Background Previous research shows inconsistent results about the stability of SOC during the childbearing period, and few studies have focused on longitudinal measures. There are contradictory results regarding the association between SOC and birth outcome. The link between levels of SOC and parental stress needs to be further explored. Aim The aim of this study was to investigate changes in SOC from early pregnancy to one year after birth and associations with background characteristics, birth outcome and parental stress. Methods A longitudinal survey of a national cohort of Swedish speaking women during 3 weeks in 1999–2000. Data were collected by questionnaires in early pregnancy, 2 months and 1 year after birth. Results SOC increased from pregnancy to 2 months after birth but decreased 1 year after birth. SOC was associated with women's background characteristics, emotional wellbeing and attitudes, but not with labour outcome. Women with low SOC reported higher parental stress after one year. Conclusion Sense of coherence is not stable during the childbearing period and is associated with women's sociodemographic background, emotional health and attitudes, but not with reproductive history or birth outcome. Parental stress is negatively correlated with SOC, and some important characteristics are similar in women having low SOC and high parental stress. Identifying women with low SOC in early pregnancy could be a means to prevent later parental stress.