October 27, 2010

Half Of Infants Sleep All Night By 4 Months Of Age

A new study finds that roughly half of all infants have the ability to sleep through the night at just three to four months of age. However, researchers note that a small number of babies will still be unable to maintain uninterrupted sleep through the night before reaching their first birthday.

"From five months on, and earlier for some families, parents can realistically expect to experience an uninterrupted and substantial period of sleep," said lead researcher Dr. Jacqueline Henderson of the University of Canterbury in New Zealand in an interview with Reuters.

Dr. Henderson and her colleagues examined sleep patterns during the first year of life for 75 healthy, full-term infants. The researchers explored three different criteria for sleeping through the night: midnight to 5 a.m.; sleeping through an unspecified eight hours of the night; and the eight hours from 10 p.m. to 6 a.m. -- a pattern resembling a typical family's sleeping habits.

Parents created a diary for six days of each month for one year, with accuracy verified by time-lapse video.

The researchers found that the biggest increase in uninterrupted sleep occurred between the ages of one to four months, during which time the babies slowly grew their sustained sleep time by nearly three hours.

By five months of age, half of infants were able to sleep from 10 p.m. until 6 a.m.

However, the babies achieved the other, less-stringent milestones at an even earlier age, with half sleeping from midnight to 5 a.m. by just three months of age.  Additionally, half were able to sleep for 8 unspecified, continuous hours by the age of four months, the scientists reported.  By their first birthday, 85 percent of the infants met these two criteria, yet one-in-four were still unable to sleep from 10 p.m. to 6 a.m.

"Many infants have difficulties in consolidating their sleep and frequently wake during the night, which is a source of distress for the family," Avi Sadeh of Tel Aviv University in Israel told Reuters.

"Understanding normal maturation may help in developing interventions and early prevention tools," said Sadeh, a clinical psychologist with expertise in children and families, who did not take part in the current study.

Such tools could include creating a quiet, dark sleep environment at an appropriate temperature, maintaining routines and sleep schedules, and slowly increasing intervals between night feedings, Sadeh said.

"Parents should be aware that the developmental process by which infants learn to sleep at night with minimal interruptions occurs very rapidly during the first six months," he said.

"And if they do not see a tendency toward better sleep during these months they should consider consulting a doctor regarding potential physical or medical factors that may play a role in disrupting sleep."

The study was reported online October 25, 2010 in the journal Pediatrics. 


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