Nocturnal awakenings are frequent among 6-month-old children, but sharing bed might make things worse.

Bedsharing reduce infants sleep duration and leads to a higher number of awakenings, a new study suggests.

Even though the researchers find an overall reduction in both sleep duration and nocturnal awakenings from 6 to 18 months of age, the chronicity of sleep problems was high - and impacted by prior sleep behavior and sleeping arrangements.

"Bedsharing was an independent and graded predictor of nocturnal awakenings, and short sleep duration, also after controlling for prior sleep", they point out.

- One third of the infants who experienced nocturnal awakenings at six months age, still had awakenings each night at 18 months of age. They had shorter total sleep duration during the night, and more frequent awakenings than other children, says researcher and first author Mari Hysing at Uni Research in Bergen, Norway.

A total of 55,831 mother reports of child sleep were used in the study to estimate the stability and predictors of awakenings and short sleep.

The study is published in Journal of Developmental and Behavioral Pediatrics.

The longer the child shared bed with their parents, the greater the chance was of short sleep duration and frequent awakenings at 18 months of age.

Breastfeeding was related to frequent awakenings at six months age, but not associated with sleeping problems later.

In the study, the definition of bed sharing were children who slept more than half the night alongside their parents.

The project is a collaboration between researchers from Uni Research Health, Norwegian Institute of Public Health and University of California, Berkeley.

The data come from the unique Norwegian Mother and Child Cohort Study (MoBa), conducted at the Norwegian Institute of Public Health.