Babies who have just started crawling tend to wake up more often at night than before, says a new study.

The study included 28 healthy babies. Researchers examined these babies once every two or three weeks. Their motor development and sleeping patterns were observed beginning at age 4-5 months and continued till 11 months.

Babies' sleep patterns were measured by sleep monitoring device and the researchers also obtained information of their sleep habits from the babies' parents. The infants' crawling development was observed and recorded.

Researchers found that babies generally began crawling by the age of 7 months and this was accompanied by an increase in number of times they woke up at night, from 1.55 times per night to 1.98 times. Once awake, babies also tended to stay awake for long, an average of ten minutes longer than usual, as per reports obtained from parents.

Also, babies who started crawling early woke up more often and moved a lot during sleep, while babies who started crawling late tended to just wake up more often, researchers found.

However, the good news for parents is that this behavior subsides and babies return to normal sleeping patterns in about 3 months from when the baby learns to crawl.

But, why does sleeping behavior changes when the babies start crawling? Researchers say that there may be many reasons.

"It is possible that crawling, which involves a vast range of changes and psychological reorganization in the babies' development, increases their level of arousal, influences their ability to regulate themselves and causes a period of temporary instability that expresses itself in waking up more frequently," says Dr. Dina Cohen of the University of Haifa's Department of Counseling and Human Development.

In babies who learn to crawl early, the restlessness could be a sign that the baby fears the physical separation from the mother before fully developing the psychological mechanism to deal with the separation. "This fear is likely to be expressed in sleep interruptions during the night," she said.

"With ongoing monitoring of babies' development, we can demonstrate that the increased awakenings are a temporary short-term phenomenon, which occurs as part of a wider process of the baby's gradually improving ability to regulate states of sleep and wakefulness," adds Dr. Cohen.