Setting

The study was conducted within the HP4All program. This program started in 2011 and was financed by the Dutch Ministry of Health, Welfare and Sports. It included preventive interventions in the preconception period (PCC) and antenatal period (new approach to antenatal risk-assessment) with the ultimate aim to improve pregnancy outcomes and reduce perinatal health inequalities in the Netherlands [16]. To attain maximum effect, the interventions were delivered in high-risk neighborhoods (zip code areas) in 14 selected municipalities with perinatal mortality and morbidity rates above the national average. The selection process of the municipalities has been described elsewhere [16]. Five municipalities were clustered as they were relatively small and belonged to the same province. As a result, we refer to a total of ten municipalities in this study. In these municipalities, the target population of the study is defined as women of reproductive age (i.e. 18–41 years). Therefore, the target population was 165,615 women. The annual number of pregnancies of about 11,058 women reflects the potential number of candidates for PCC.