Little in Norway (LiN) study

Child outcome and possible diagnostic information based on repeated observations of parent–child interaction, developmental testing, and parent and preschool teacher report measures:

Data collection in the Little in Norway study has comprised five points in pregnancy (weeks 16, 20, 26, 32, 36), time of birth, 6 weeks postpartum, 6,12 and 18 months and 3 years. Data have been collected through self-report questionnaires filled out at home, at well baby clinics or completed by research assistants based on parent interviews, and by testing and observation of the child, telephone interviews and video sessions. All completed questionnaires, test protocols and video recordings were streamed to a central facility where they were registered, verified and kept on a secure server. The questionnaires that were completed at home used a web-based survey motor provided by one of the study’s data processors.

A comprehensive questionnaire package was given to the participating mothers and fathers at the first meeting in pregnancy, which could take place from pregnancy week 8 to 34, depending on the specific time of enrolment. The questionnaire package included queries concerning sociodemographic background, smoking, use of alcohol, drugs and medication in pregnancy, as well as the following measures:
1. The Life Stress Scale (a subscale of the Parenting Stress Index, PSI), measuring parental stress factors over the previous 12 months
2. The Pregnancy Related Anxiety Questionnaire (PRAQ R), designed to assess anxiety related to pregnancy and birth
3. The Edinburgh Postnatal Depression Scale (EPDS), a self-report measure identifying women at risk for perinatal depression
4. The Adverse Childhood Experience Scale (ACE), assessing possible parental adverse childhood experiences prior to age 18 years
For all but the latest enrolled families, most of the procedures applied at the first meeting were repeated at follow-ups later in pregnancy. When a project infant was born, the research assistant at the site collected information from hospital birth records.

At 6 weeks after birth the research assistants met with the parents and their baby to observe the infant and to obtain information about the child’s diurnal rhythm. Questionnaires were given to the parents and biological samples from the mother and the child were collected:
EPDS (6 weeks, 6, 12, 18 months) and PSI (long version) answered by the parents also after birth (6, 12, 18 months)
1. The child’s developmental skills were assessed by testing the child’s cognitive, language, and fine- and gross motor development using the screening (6 and 12 months) or the full version (18 months) of the Bayley Scales of Infant and Toddler Development, third edition (Bayley-III)
2. The infants’ possible social withdrawal reactions were observed in a standardized way (using the Alarm Distress Baby Scale) based on child behaviour when completing the Bayley
3. Infant social emotional functioning assessed in a videotaped interaction session, first with one of their parents present and then with the other, and subsequently coded by means of the Relational Health Screen.
4. Perceived temperament of the participating infants assessed with a questionnaire at 6 and 12 months
5. Child social emotional functioning assessed in a sub-sample by a standardised telephone interview, based on Infant–Toddler Social–Emotional Assessment (ITSEA), with the main caregiver at 12 months. At 18 months, ITSEA was completed by all parents at the site, and also by the child’s preschool teacher if the child attended a day-care centre. At 3 years a web-based Version of the questionnaire ITSEA was completed from home

1. Dietary intake was assessed using a web-based, semi-quantitative food frequency questionnaire, the Seafood-FFQ. The questionnaire is designed to capture the habitual intake of seafood and the use of dietary supplements. To enable aggregation and quantity estimation of individual seafood consumption, ordinal data from the Seafood-FFQ is converted to numerical data using the seafood-index system. At 3 years a web-based FFQ of mothers and children's food habits was applied.
2. Nutritional status and suboptimal nutritional status of micronutrients like DHA, vitamin D and iodine, assessed using hair, urine, and blood samples collected repeatedly through follow-up (at inclusion in pregnancy, 6 weeks, 6 months, 12 months and 18 months)
3. Cortisol level measured using hair samples from mothers 6 weeks and 12 months postpartum
4. DNA methylation assayed using saliva samples collected by the research assistants at 6 weeks and 12 months (from the child and the mother)