Babies imitate the mother’s sleep pattern

Parents of children under the age of two often feel that their sleep is inadequate and are outright tired. A Finnish study reveals that the mother's preferred circadian rhythm i.e. chronotype is connected to the child’s sleep pattern development. The baby will stay awake if the rest of the family does so.

The study in question is a collaboration between The National Institute for Health and Welfare, Helsinki University Hospital’s Pediatric Research Center, Pirkanmaa Hospital District, University of Helsinki, Tampere University, and University of Eastern Finland. This recently published study examined for the first time the connection between the parent’s partially genetic chronotype and the child’s sleep pattern. The study is based on the CHILD-SLEEP cohort collected in the Pirkanmaa region in 2011–2017.

Research showed that the children of mothers who are evening people have more difficulties in developing sleep patterns when compared to others. The father’s chronotype had no effect.

The study followed 1,220 mothers and 1,116 fathers whose sleep quality and circadian rhythm were gauged via questionnaire forms during the pregnancy and when the child was three, eight, 18, and 24 months old. The children’s sleep was monitored at the same points in time.

Under-two-year-old children showed similar "eveningness” in their circadian rhythm as their mother. This manifested as a difficulty to settle down to sleep in the evening and as a late bedtime. More sleeping difficulties were also reported.

The incidence of sleep problems is at its highest during the first two years of a child's life, but their connection to the parents’ circadian rhythm has not been studied previously.

Juulia Paavonen, MD, docent, says that we know from adult sleep studies that being an evening person in the first place is a risk for sleeplessness, delayed sleep period, and daytime tiredness.

“Eveningness in the circadian rhythm of an under-two-year old child did not seem to affect the total amount of sleep. Babies of mothers who are evening people take longer naps, which then shortens the night-time sleep.”

Families can change their habits

The first two years of a child’s life are crucial for sleep pattern development and the development is governed by the family's habits.

“According to our study, eveningness in families with an infant increased the amount of problems with sleep patterns, and delayed circadian rhythm development. This presents itself as waking up at night or having trouble falling asleep in the evening, says Paavonen, who is specializing in pediatric psychiatry.

In her experience, sleep school is not always needed. Families can instead be helped in making corrective adjustments to their sleep pattern.

“This study does not provide us with direct answers regarding the child's chronotype, but making changes to the whole family's daily cycle will also support the infant's sleep pattern development. Their sleep pattern will develop as part of the whole family’s sleep pattern. The infant has very little means of regulating their sleep pattern independently", Paavonen points out.

After all, the most important result of the study is the observation that the family's daily cycle affects what kind of a sleep pattern the child adopts.

The National Institute for Health and Welfare, Helsinki University Hospital’s Pediatric Research Center, Pirkanmaa hospital area, University of Helsinki, Tampere University, and University of Eastern Finland participated in the study. The study was funded by Academy of Finland, Gyllenberg Foundation, and Foundation for Pediatric Research, among others.

Morales-Muñoz I, Partonen T, Saarenpää-Heikkilä O, Kylliäinen A, Pölkki P, Porkka-Heiskanen T, Paunio T, Paavonen E J.
The role of parental circadian preference in the onset of sleep difficulties in early childhood

Further information:
Docent Juulia Paavonen, HUS and University of Helsinki, juulia.paavonen@helsinki.fi, 050 428 6524