BACKGROUND: This study aimed to explore socioecological correlates of parental lifestyle patterns during pregnancy, an overlooked topic except for individual socioeconomic factors. METHODS: We used data from three European mother-offspring cohorts participating in the EndObesity Consortium [EDEN, France, n = 1,962
Generation R, the Netherlands, n = 8,765
and Lifeways, Ireland, n = 932]. In previous principal component analysis, we identified two separate parental lifestyle patterns in pregnancy, characterised by: 1) "high parental smoking, poor-quality maternal diet, and low physical activity"
and 2) "low parental body mass index (BMI) and high gestational weight gain (GWG)". Applying the socioecological model, we conducted multivariable linear regression analyses on lifestyle pattern scores (outcomes), first including parental socioeconomic and sociodemographic characteristics (block 1), then the urban environment (block 2), and finally psychosocial factors and health-care access (block 3). RESULTS: Older parents, those born abroad, or with high SEP had lower scores for the first lifestyle pattern. Conversely, multiparous mothers, those with suboptimal health insurance coverage, or who did not attend parenting preparation sessions followed that pattern more closely. Multiparous mothers, parents with a low SEP, or living in highly deprived areas had lower scores on the second pattern, contrary to those exposed to high population density or living in a neighbourhood with high facility richness. CONCLUSIONS: Higher SEP, a foreign birthplace, wealthier neighbourhoods, and attendance at antenatal parenting preparation sessions were associated with healthier parental lifestyles during pregnancy. These potential facilitators should be considered for inclusion in tailored family-based health promotion interventions during the perinatal period.