Abstract Background Maternal overweight and obesity are related to several health risks in the periods before, during and after pregnancy including a higher risk of gestational diabetes mellitus, preeclampsia and preterm birth. At the same time, women’s daily life quickly changes in these periods. Therefore, we hypothesize that the value of determinants of lifestyle behavior within different levels of the socio-ecological model differ accordingly and influence lifestyle behavior. These dynamics of determinants of lifestyle behavior in the periods before, during and after pregnancy are unexplored and therefore evaluated in this study. These insights are needed to offer appropriate guidance to improve lifestyle in women of childbearing age. Methods Individual semi-structured interviews were conducted before, during or after pregnancy in 26 women with overweight or obesity living in the Netherlands. Questions covered all levels of the socio-ecological model, i.e. intrapersonal, interpersonal, institutional and ...