Background CenteringPregnancy (CP), a model of group antenatal care, was implemented in 2012 in the Netherlands to improve perinatal health; CP is associated with improved pregnancy outcomes.... Show moreBackground CenteringPregnancy (CP), a model of group antenatal care, was implemented in 2012 in the Netherlands to improve perinatal health; CP is associated with improved pregnancy outcomes. However, motivating women to participate in CP can be difficult. As such, we explored the characteristics associated with CP uptake and attendance and then investigated whether participation differs between health care facilities. In addition, we examined the reasons why women may decline participation and the reasons for higher or lower attendance rates. Methods Data from a stepped-wedge cluster randomized controlled trial were used. Univariate and multivariate logistic regression models were used to determine associations among women's health behavior, sociodemographic and psychosocial characteristics, health care facilities, and participation and attendance in CP. Results A total of 2562 women were included in the study, and the average participation rate was 31.6% per health care facility (range of 10%-53%). Nulliparous women, women 30 years old, and women reporting average or high levels of stress were more likely to participate in CP. Participation was less likely for women who had stopped smoking before prenatal intake, or who scored below average on lifestyle/pregnancy knowledge. For those participating in CP, 87% attended seven or more out of the 10 sessions, and no significant differences were found in women's characteristics when compared for higher or lower attendance rates. After the initial uptake, group attendance rates remained high. Conclusion A more comprehensive understanding of the variation in participation rate between health care facilities is required, in order to develop effective strategies to improve the recruitment of women, especially those with less knowledge and understanding of health issues and smoking habits. Show less