Body Weight, Body Composition and Energy Balance Related Behavior During the Transition to Parenthood

Understanding critical periods during which people are at risk to gain weight or display unhealthy changes in energy balance related behaviour, i.e. eating, physical activity and sedentary behaviour, can facilitate the development of weight gain prevention programs. Although the transition to parenthood is associated with pregnancy-related weight gain and retention in women, evidence on the effect of having a first child on men's body weight is lacking. It is also unclear whether pregnancy-related weight gain and retention cohere with unfavourable changes in body composition and energy balance related behaviour in both women and men transitioning to parenthood. Using a mixed-methods design, the investigators aim to provide insight into this critical life phase. An observational follow-up study will be used to investigate changes in body weight, body composition and energy balance related behaviour among couples from pre-conception to one year postpartum, and to identify those most at risk for excessive weight gain.

The first objective of this research is to investigate both maternal and paternal changes in body weight, body composition and energy balance related behaviour during and after pregnancy in Flemish couples.

The second objective is to investigate socio-demographic and behavioural predictors of changes in both maternal and paternal body weight and body composition, in order to identify those most at risk for postpartum weight gain and retention.

Couples transitioning into parenthood (age ≥ 18 years, any BMI and socio-economic status) will be recruited during the first trimester of pregnancy by gynaecologists from the partner obstetrics units at five Flemish hospitals. All couples expecting their first child will be asked to participate in the study. Participants below 18 years of age, not speaking the Dutch language or suffering from a pathological condition that may influence energy balance related behaviour (e.g. diabetes, preeclampsia etc.) will be excluded.

Using a longitudinal design, participating couples (women and men) will be measured four times over the course of approximately one year and nine months. Baseline measurements (T0) will take place during the first trimester of pregnancy (at 12 weeks of pregnancy), with follow-up measurements at respectively six weeks (T1), and six (T2) and twelve months (T3) postpartum.

At baseline (T0), both retrospective and prospective measurements will be conducted in both pregnant women and men expecting their first child. Retrospectively, a self-report questionnaire will be used to assess body weight, height and energy balance related behaviour, incl. eating (Food Frequency Questionnaire (FFQ) which will be adapted for pregnant women), physical activity (International Physical Activity Questionnaire (IPAQ - Dutch version) and sedentary behaviour. The self-report questionnaire will also include questions about sleeping habits, smoking, and socio-demographics. Prospectively, body weight (SECA digital weighing scale), height (SECA stadiometer), body composition (TANITA Bioelectrical Impedance Analyzer \& skin fold thickness measurements at the biceps, triceps, subscapular and suprailiac sites) and waist circumference (Cescorf measuring tape) will be objectively measured. Women's gestational weight will be monitored by the gynaecologists as all pregnant women are being weighed during consultation. The same self-report questionnaire (see supra) will be used prospectively, including extra questions about breastfeeding and parental leave. In addition, dietary intake will be assessed by a 3-day food diary, whereas tri-axial accelerometers (Actigraph) will be used to measure energy expenditure (by rate of physical activity and sedentary behaviour) objectively over a one-week period. At followup moments (T1-3), the same aforementioned prospective measurements will be carried out.

Eligibility Criteria:
Inclusion Criteria:

* Couples expecting their first child (nulliparous women and men)
* Participants aged ≥18 years
* Participants with any BMI
* Participants from any socio-economic status (SES)
* Participants have a sufficient proficiency of the Dutch language

Exclusion Criteria:

* Participants unable or unwilling to give informed consent
* Participants below 18 years of age
* Participants not speaking the Dutch language
* Participants suffering from a pathological condition that may influence energy balance related behaviour (e.g. diabetes,), with significant psychiatric disorder, with history of a bariatric surgery, or with requirements for complex medical diets.
* Participants who are - because of medical or other specific reasons - not allowed to exercise (e.g. bed-rest).
* Women having a multiple pregnancy (twin, triplet,...).