RESUMEN
BACKGROUND: Becoming a parent may cohere with drastic changes in physical activity (PA) and sedentary behavior (SB). A clear understanding of determinants of changes in PA and SB during pregnancy and postpartum is needed to facilitate the development of tailored family-based interventions. METHODS: Thirteen focus group discussions targeting determinants of changes in PA and SB behavior were conducted, involving a total of 74 expecting and first-time parents. A semi-structured question guide was used to facilitate the discussions. RESULTS: Four main levels of determinants were identified: the individual (including psychological, situational and biological determinants), interpersonal, environmental and policy level. Some determinants were mentioned to be a barrier (e.g., "barriers to self-care") while others were a facilitator (e.g., "weight control"). Determinants were related to both PA and SB and applicable during pregnancy as well as postpartum (e.g., "self-regulation"), or only related to one behavior and/or one period (e.g., "feeding baby"). Some were described by both parents (e.g., "parenthood perceptions"), whereas others were mentioned by women (e.g., "PA knowledge") or men (e.g., "time opportunities") only. CONCLUSIONS: Focus should be given to interventions aimed at improving parents' self-regulation skills and support on how to cope with interpersonal and situational constraints as well as parenthood perceptions.
