432 B. Kerstis et al. study and information about how to contact the research team was attached to each questionnaire. The baseline questionnaire was answered at the CHC, while the follow-up questionnaire was sent to the parents’ home by mail when the child was 3 months old. This latter questionnaire was returned by mail in a prepaid envelope. A postal reminder, including an identical questionnaire, was sent once to those who did not reply within 3 weeks. A second reminder occurred by telephone 5 weeks later. All questionnaires were decoded and depersonalized before analysis. Due to a printing error in the baseline questionnaire, questions regarding the Dyadic Adjustment Scale (DAS) were not included in about one out of four of the baseline questionnaires, meaning that 96 couples had to be omitted from the data set. Of the remaining participants, 32 of the couples did not answer both questionnaires. The sample used in the present study thus consisted of 305 couples (Figure 1). Ethical considerations Ethical permission to conduct the study was granted by the Central Research Ethics Committee of Stockholm. Measures Dyadic Consensus Subscale (DCS) DCS is a part of the Dyadic Adjustment Scale (DAS), which is a comprehensive instrument intended to assess relationship quality and evaluate possible needs for therapy according to four subscales: Dyadic Con- sensus, Dyadic Satisfaction, Dyadic Cohesion, and Affectional Expression (26). DAS can be used by women as well as men (28) and permits comparisons of partners’ scores and assessments of individuals in married and unmarried cohabiting couples (29). The subscales can be used alone, as in the present study, without losing conﬁdence in the reliability of the measure (26,30). The DCS measures agreement between partners on matters important to their relationship using 13 self-report questions (Table I) scored on a six-point Likert-type scale ranging from ‘Always disagree’ (scored 0) to ‘Always agree’ (scored 5), resulting in a maximum of 65 points (26). The higher the scores, the more the mother/father thinks that she/he and her/his spouse are agreeing; the lower, the more they perceive that they are disagreeing. The DAS was translated using a conventional test analysis and validated for Swedish conditions (31). The Couples at baseline n = 401 Couples answering the first questionnaire n = 305 Couples answering DCS + EPDS n = 249 Missing data n = 96 Couples not answering DCS + EPDS n = 56 Figure 1. Included couples of the present study.