New-born babies do not know the difference between night and day and certainly do not have a watch. They sleep on and off during the day and night, approximately 14-17 hours every 24 hours.
They have two kinds of sleep, quiet sleep, and active sleep. In quiet sleep, baby breathes a bit more regularly and is still. In active sleep, they suck, jerk, move around, and may twitch, smile, flutter their eyelids, grunt, or even cry. All this movement and noise can be hard to get used to and often fools you into thinking baby is waking when they're not.
They move through these sleep cycles every 40-50 minutes. It is common for them to wake up after a cycle and will often need help to get back to sleep.
When you first take baby home, at about 2-3 days old, baby might be feeding quite frequently as your milk might be just starting to “come in”, and they are starting to get hungry now. This first night home can often be more unsettled than the last few days as it is a new environment for baby. It’s a new situation for you too, and when your milk is coming in and baby is feeding a lot they tend to have a lot more dirty nappies. So, be mentally prepared for baby to not be that settled for this first night at home. It definitely will get better!
Regular feeding in the first couple of weeks:
I often suggest to parents that baby needs a certain amount of feeding in a 24-hour period, and if we let them sleep too long, especially during the day, they will need to make this up and feed during the night. We talk about feeding every 3 hours, a 2-hour sleep, and up feeding for approximately 1 hour (includes changing, winding, and cuddling).
There are a lot of benefits to regular feeding in the early days, it helps their gut to work, helps flush out any Jaundice, and aids in building a good milk supply. Babies often lose about 6-8% of their initial birth weight. Regular feeding helps to replace this weight loss, making them more robust so they can now feed more when they are hungry and it might also stretch feeds out overnight to 4 hours.
New-borns, once your milk is in, often fall asleep after 4-5 minutes into the feed. They have that first let-down of milk, get all sleepy (soporific), and if they are dressed too warm, stay asleep, and don’t feed enough to sleep very long. I suggest taking all wraps off and a layer of bay clothing so they are cooler, this will help them have a much better feed, resulting in better sleep.
Research suggests babies take approximately 3-5 months to achieve a solid 5-hour sleep, this is due to them not producing enough melatonin yet. Good sleep is known to help with growth and immunity, which is why new-borns tend to need more in those early months.