Sleep and health during the first 1000 nights

Given the importance of sleep for both our physical and mental health, developing good sleep health is pivotal. In the introductory chapter 1 we describe that the development of sleep starts during the period between conception and a child’s second birthday, in this thesis referred to as the first 1000 nights of life. In this period fetal brain structures develop, as is the child’s sleep-wake rhythm. The environment of the child is known to influence adaptive responses and potential epigenetic mechanisms. This was first hypothesized by Barker and is also known as 'fetal programming'. Emergent themes in fetal programming are effects of psychological or physiological stress during the first 1000 nights. Sleep health during this period could be one of these stressors and we therefore studied the association with later childhood sleep and health. The overall theme of this thesis is a public health perspective on sleep during the first 1000 nights. The axiom is that developing good sleeping habits early on in life, may result in a life-long benefit, not only for sleep itself, but also for cognitive and behavioral development and cardio-metabolic health. The first research question was ‘What is the association of sleep during early stages of life (between conception and the second birthday) and childhood cardio-metabolic health outcomes (age 4-12 years)?’ The second research question was ‘What are potential determinants and parental health care needs regarding sleep in early life (between conception and the second birthday)?’ Our main conclusions are: A. Sleep and health of mother and child have a bi-directional relationship and are affected by multiple environmental factors during the first 1000 nights. B. Infant problematic sleep is common and often coincides with excessive infant crying as well as mental complaints in parents. C. Problematic sleep seems persistent from infancy to childhood. Our findings support the hypothesis of fetal programming in the development of sleep health. Fetal programming is affected by the in-utero and early life environment. We found environmental determinants during pregnancy and infancy that had a strong association with later childhood sleep problems. Our final conclusion is that infant sleep problems are common and often coincide with excessive infant crying as well as mental complaints in parents. During the first 1000 nights, sleep and health of mother and child have a bi-directional relationship. Sleep problems can originate from various environmental factors during the first 1000 nights and can be persistent from infancy to later childhood. Health care support should, in addition to alleviating infant crying or sleep problems, also address parental wellbeing.