Table 3 Additional information

 Medical checklist

x

During the telephone call in pregnancy the medical checklist will be filled out to examine severe physical and mental health problems. In addition, eligibility questions will be answered: age, language proficiency, singleton versus twin pregnancy.

 Self-developed delivery questionnaire

x

Infant weight, Apgar, birth and delivery complications, born ≥37 weeks of pregnancy

 Demographics questionnaire

x

Maternal age, educational level, SES, drugs use, alcohol use, smoking, number of siblings, age of siblings.

 Self-developed delivery questionnaire

x

Infant sex.

 Daily logbook/weekly logbook/questionnaire on physical contact

x(w1–12)

x

Mothers will register 1) holding, 2) SSC, and 3) no contact, as three distinct behavioural categories, for every 15 min with simple lines for the first 5 weeks after birth. In the daily logbook, mothers are able to discriminate between holding and SSC by the mother or other caregivers. Between week 5 and week 12, all mothers will note the estimated time spent in daily holding and SSC on a weekly basis. During the follow-up assessment at 1 year after birth, mothers will indicate how many weeks after week 12 they provided SSC to their infant.

 Maternal prenatal depressive symptoms, anxiety, and stress

x

The EPDS to screen for depressive symptoms [53].

The Pregnancy-Related Anxieties Questionnaire-Revised (PRAQ-R) is a 34-items validated questionnaire to screen for pregnancy related anxieties [71].

The STAI to screen for anxiety [54].

The Pregnancy Experience Scale (PES) is a 43-items validated questionnaire to assess perceived maternal appraisal of pregnancy-related daily hassles [72].

A 20-item self-developed questionnaire to examine worries related to the preparation for the baby’s arrival.

The APL to screen for the occurrence and intensity of daily hassles [55].

 Mother-infant bond

x

The Maternal Antenatal Attachment Scale (MAAS) is a 19-item validated questionnaire to assess maternal attitudes, thoughts, and feelings towards the unborn child [73].

 Self-developed delivery questionnaire

x

Number of days the father stayed at home after birth.

 Weekly logbook sleep location & night awakenings

x(w1–12)

The mother will register the primary sleep location of the infant during 00.00–05.00 h for the previous week [47, 74]. Also, the average number of night awakenings of the infant between 00.00–05.00 h will be noted in the weekly logbook.

 Parental ethnographies questionnaire

x

x

10-item questionnaire to assess cultural conceptions on parenting [75].

 Social support questionnaire

x

x

Adjusted version of the Social Support Effectiveness Questionnaire (SSE-Q) to examine instrumental, informative and emotional partner support, and negative affect [76].

 Social touch

x

The Social Touch Questionnaire (STQ) is a 20-item questionnaire to assess attitudes towards social touch [77].

 Adult attachment

x

The Experiences in Close Relationships Scale (ECR) is a validated 36-item questionnaire to asses adult attachment to her current and previous partners [78].