Genes to Blame for Baby's Nighttime Sleep Patterns, Not Environment

A new study shows that genes play an important role in a baby's sleep at night.

Researchers in Canada looked at records from nearly 1,000 identical and fraternal twins in Quebec, to find that genes largely determine whether they would sleep through the night. However, they noted that a child's ability to nap throughout the day is more likely defined by the environment.

If parents are having difficulty getting their child to sleep soundly, there may be some easy ways to aid the process.

"The genetic influence is only part of the equation that controls sleep duration. One should not give up on trying correcting inadequate sleep duration or bad sleep habits early in childhood," said study author Evelyne Touchette, a psychology researcher at Laval University in Quebec.

The researchers found there is a particularly sensitive time for the influence of parental interventions, at around 18 months, Touchette said. "This is a good time to implement sleep strategies in order to improve the child's nighttime sleep habits if they are not already in place," she said.

Only 5 percent of children in the study were considered "short-persistent sleepers," meaning they seemed to need less than 10 hours of sleep per night. Thus, parents need to address these problems immediately so they do not cause further health concerns with their child. 

In the study, the researchers did not look for specific genes associated with sleep, rather they looked at whether identical twins were more likely than fraternal twins to share sleep patterns.

While children can vary in their sleep habits, there are some milestones to look for, said Dr. Dennis Rosen, associate medical director of the center for pediatric sleep disorders at Boston Children's Hospital and author of "Successful Sleep Strategies for Kids" (Harvard University, 2012).

At 6 weeks old, infants begin napping two to three times a day, moving to two daily naps by age 6 months, he said. At 18 months, a toddler should be down to one nap during the day.

In the Quebec study, 4 percent of children had stopped napping by age 4, but that number was 68 percent in a similar study from Italy, showing culture has some impact on nap times.

It's key to find balance between spending enough time in bed but not too much time, Rosen said, according to Live Science.

Researchers note that if a child is waking up multiple times, snoring, gasping for breath or taking pauses in between breaths, these can all be concerns that need to be investigated.