If your baby isn’t sleeping through the night by the time he is 12 months old, don’t worry.

Researchers with the Maternal Adversity, Vulnerability and Neurodevelopment team, which included scientists from Montreal, Singapore and Hamilton, Canada, studied a cohort of 388 mothers and infants. When the babies were 6 months old and then again when they were 12 months old, mothers answered questionnaires about how many consecutive hours their babies slept during the previous two weeks. Additionally, researchers examined the mothers’ moods and how well the infants were developing in cognitive and language skills, as well as gross and fine motor skills, according to the December 2018 issue of Pediatrics.

At six months, 60.4% of mothers reported their children slept six uninterrupted hours or more a night and 43% slept eight hours or more. By 12 months, 72.1% were sleeping in six-hour blocks or more and 56.6% were sleeping a full eight.

On the flip side, that means 39.6% of 6-month-old babies weren’t sleeping at least six hours straight and 27.9% of 12-month-old children weren’t getting those long blocks of uninterrupted sleep.

Researchers found that the children’s mental and psychomotor development weren’t affected by sleep. Similarly, mothers didn’t appear to have any greater depression symptoms whether their child was sleeping a full six or eight hours or not.

Since there is such a wide variability in when babies learn to sleep through the night, parents might want to change their expectations of when the entire family will get a full night’s rest, the researchers noted.

  babies and sleep