We tend to believe parents and friends when they tell us our baby is sleepy, grumpy or hungry because they’re having, or about to have, a growth spurt. Most of us have probably never really questioned whether or not this is true or whether it is an old wives’ tale. Or even a myth we accept because it makes us feel better to have a reason why our baby is slightly out of character or routine.
Well now there’s proof! A professor of anthropology at Emory University in the United States conducted a study to see if there really is truth behind the myth. The study asked 23 sets of parents to keep a sleep diary for their baby. Results showed that babies can sleep up to a whopping 4 ½ hours longer in the day for two days, before a growth spurt.
Parents were asked to record sleep and waking times, whether the baby was breast or formula fed, and any other physical signs, such as illness (e.g. temperature, vomiting, rash) from when they were newborn (on average the diaries started at around 12 days) right through for between 4 and 17 months. Of the 23 babies studied there were 9 boys and 14 girls.
The researchers regularly measured the babies’ length (some of them weekly, some twice a week and some daily) and found a baby was 43% more likely to grow for each extra nap they had and 20% more likely for each extra hour. They got heavier as well as taller in this period, laying more fat around their tummies in particular. The study also showed that boys slept more often but for shorter periods of time. Breastfed babies also had shorter, more frequent naps.
The theory is that babies don’t just grow more in their sleep but they also produce higher levels of growth hormones when they are in deep sleep. This is thought to encourage bone growth, which explains why children can wake up in the night complaining of aching bones (and probably babies too, but they can’t explain it!).
The results weren’t perfect; we all know babies aren’t that predictable! An increase in sleep wasn’t always followed by a growth spurt and a growth spurt wasn’t always preceeded by increased sleep. But it does show that there is a strong link between your child’s development and their sleep patterns.
What do you think? Does it make you feel better to know there is a reason for changes in your baby’s routine or sleep pattern? Have you noticed that your baby sleeps more for a couple of days and then suddenly nothing fits them?!