Tuesday, August 17, 2010

Infant Sleep Update

As we share information about Baby Behavior with more people across the US (and beyond) we find, without a doubt, one of the most controversial and engaging topics continues to be infant sleep. Parents are bombarded with information about how their babies should sleep and “sleeping through the night” continues to be regarded as a milestone to be achieved sooner rather than later. When I was new to motherhood myself (see “Thoughts from a Sleep Deprived Mom”), I was not prepared for how much my daughter would wake during the night and how little sleep she (and I) would get each night. While pregnant, I held the expectation that babies needed a lot of sleep and thus would sleep all the time (remember the phrase “sleep like a baby”? Where on earth did that come from?) Well, with my daughter’s birth came a huge wake up call: although babies do need a lot of sleep, they don’t necessarily need as much sleep as parents might think they do, and they certainly don’t consolidate their daily sleep needs into one nice 8-hour stretch during the nighttime...at least for awhile.

To further shed light on this divisive topic, we would like to report some of the findings of a large study that looked at sleep patterns in children from age 1 month to age 16 years. As you read on, keep in mind that 1) Every baby is different and 2) An infant’s sleep can vary from one day to the next. For more information, click here to view our 4-part series about the Science of Infant Sleep.

~Study Findings~

How many hours do babies sleep per day during a 24-hour period?
Total hours of sleep decrease with age with 1 -month-old infants sleeping an average of about 14 ½ hours per 24 hour period and 18-month-old toddlers sleeping about 1 hour less per 24 hour period (~13 1/2 hours). You’re probably wondering how your baby could possibly sleep LESS as he gets older, but what actually happens is that over your baby’s 1st year of life, his nighttime sleep consolidates into a longer stretch as his daytime sleep (naps) decrease.

How many hours do babies sleep during the nighttime?
Results of this study showed that the average one-month-old infant sleeps about 8 hours during the nighttime. (Note: this study reported nighttime sleep as time spent in bed.) By 3 months, babies spend about 10 hours per night in bed and this increases to about 11 ½ hours by 18 months. This doesn’t mean the average 1-month old sleeps 8 hours straight! It just means he spends 8 hours in bed total during the night. Information about number of night wakings was not collected.

What about daytime sleep/naps?
Average daytime sleep decreases gradually over the first year with 1-month-old infants napping a total of 5 ½ hours per day and about 2 hours per day by 18 months. Also by 18 months, a big change occurs as baby changes from 2 to 1 nap per day. Just a head’s up: some babies don’t like big changes in their routine and have a very hard time dropping their 2nd nap. I can remember several months of transition during this time where my daughter would be very grumpy the days she had just one nap but then up past my bedtime the days she took two naps. Here are the research findings for the average hours of daytime sleep for ages in between 1 month and 18 months: 3 months: ~5 hours, 6 months: 3.4 hrs, 9 months: 2.8 hours, 12 months: 2.4 hours.

These days I’m looking forward to having a 2nd child, armed with the knowledge of how babies sleep and how their sleep patterns change over time. I think knowing what to expect makes us more confident as parents and less frustrated by our babies’ seemingly random behavior. I have one last finding to report: my daughter, now 3 1/2 does “sleep through the night” most of the time. There are a few little exceptions: when she is sick, when she misses her travelling mommy, when she hears funny sounds or has to get up to potty. Honestly though, I would rather her wake me for those things than find a nice wet present in her bed at 5am, and I often look forward to those crack of dawn snuggles when I’ve just returned home from two days away out of town.


Iglowstein I, Jenni OG, Molinari L, Largo RH. Sleep duration from infancy to Adolescence: Reference values and generational trends. Pediatrics. 2003 Feb; 3(2): 302-307


  1. The sleep saga!

    Our 7 month old is a better daytime napper now, yeah. He wakes twice at night and that's much preferable to every 2 hours.

  2. Great news! You're giving a lot of new parents hope for the future!