Caring for a newborn can be exhausting! Parents want to know what is normal and when will it get easier? One way to have realistic expectations is to learn a little about newborn physiology. Or in other words, thinking about how babies are designed can help you understand why they behave the way they do.
Newborns require up to 18 hours of sleep a day. Babies are born with an immature circadian system. This partly means they have shorter sleep cycles and night and day don’t yet influence when they sleep. One study showed that these systems don’t develop until 1-3 months of age (http://neoreviews.aappublications.org/content/4/11/e298.extract). This means most babies are not capable of sleeping through the night until they are older.
A sleep cycle is a pattern of light and deep sleep we all go through. Babies have sleep cycles which are shorter and less ‘deep’ than adults, so they are more vulnerable to waking. If your baby wakes after 30-45 minutes, they weren’t able to remain asleep through the transition period from light to deep sleep. If they don’t wake up, they will likely continue to sleep for another cycle before becoming vulnerable to waking again. When your baby wakes at 3am, as far as they are concerned it might as well be the middle of the day. Waking is a protective mechanism for babies, as they need to feed to grow.
A newborn baby usually feeds between 8-12 times per day. The size of the baby’s stomach dictates how much they can have at each feed. Initially the stomach is only the size of a marble and by 2 weeks it is the size of an egg. Babies will eventually become more efficient feeders and feeds will space out more. The La Lache League advises that any feeding schedule restricting a baby’s ability to feed in the first six weeks of life can potentially cause poor weight gain. National guidelines on infant feeding (see Pg 79 here) suggest giving 30-60ml/kg/day of formula for the first few days, then 150ml/kg/day of formula up to 3 months of age.
Being flexible with routines
Babies need to be given time to physiologically adapt to their new environment. As their circadian system matures and their stomach size increases, you may start to notice changes in their behaviour and start establishing some routines. But just when you think you have figured it all out a growth spurt or illness may interrupt this! So it’s important to try to remain flexible, otherwise things can get pretty frustrating.
Don’t be afraid to seek advice from health professionals when establishing age appropriate feeding and sleeping routines. I often tell people the first few weeks are the hardest and it should get easier as your baby matures. Also don’t forget to be willing to accept help from others so you can rest when possible and good luck!