BACKGROUND: There are good opportunities in Sweden for health promotion targeting expectant parents and parents of young children, as almost all are reached by antenatal and child health care. In 2005, a multisectoral child health promotion programme (the Salut Programme) was launched to further strengthen such efforts. METHODS: Between June and December 2010 twenty-four in-depth interviews were conducted separately with first-time mothers and fathers when their child had reached 18 months of age. The aim was to explore their experiences of health promotion and lifestyle change during pregnancy and early parenthood. Qualitative manifest and latent content analysis was applied. RESULTS: Parents reported undertaking lifestyle changes to secure the health of the fetus during pregnancy, and in early parenthood to create a health-promoting environment for the child. Both women and men portrayed themselves as highly receptive to health messages regarding the effect of their lifestyle on fetal health, and they frequently mentioned risks related to tobacco and alcohol, as well as toxins and infectious agents in specific foods. However, health promotion strategies in pregnancy and early parenthood did not seem to influence parents to make lifestyle change primarily to promote their own health; a healthy lifestyle was simply perceived as 'common knowledge'. Although trust in health care was generally high, both women and men described some resistance to what they saw as preaching, or very directive counselling about healthy living and the lack of a holistic approach from health care providers. They also reported insufficient engagement with fathers in antenatal care and child health care. CONCLUSION: Perceptions about risks to the offspring's health appear to be the primary driving force for lifestyle change during pregnancy and early parenthood. However, as parents' motivation to prioritise their own health per se seems to be low during this period, future health promoting programmes need to take this into account. A more gender equal provision of health promotion to parents might increase men's involvement in lifestyle change. Furthermore, parents' ranking of major lifestyle risks to the fetus may not sufficiently reflect those that constitute greatest public health concern, an area for further study.