I have a friend, a mother to four, who says she’d take all the babies if they’d come out as 4-month-olds instead of newborns. The newborn stage is a truly unique period of time: Even though a healthy, full-term infant is born fully developed and technically ready for life on the outside, so much of a newborn’s existence still seems a few months behind.
This is especially noticeable in how they sleep! Newborn sleep patterns are so different from those of an older baby (let alone an adult) that sleep in the first weeks of life can feel like a total crapshoot. But when you have an idea what to expect, it can make this oh-so-brief (but sometimes endless-feeling) stage a lot more manageable.
We’ll take a look at:
Newborn circadian rhythm
Newborn sleep pressure
Newborn sleep cycles
Newborn Circadian Rhythm
For most humans, the primary driver of our sleep patterns is the circadian rhythm–the 24-hour cycle that acts as the body’s internal “clock” and drives our sleep and wake hormones, largely influenced by variations in light. The circadian rhythm is the reason we sleep at night and are awake during the day, instead of merely catnapping our way through each 24-hour period whenever we get tired enough.
Your newborn baby, however, doesn’t have a circadian rhythm. Born with an underdeveloped pineal gland, they won’t fall into a reliable pattern of cortisol and melatonin production until at least 8-9 weeks of age. Coupled with the fact that they just spent their entire existence in the constant darkness of the womb and are still developing other systems that play a role in sleep (such as body temperature regulation), they really couldn’t care less if it’s day or night!
Don’t be surprised if your baby seems to sleep all day and be wide awake half the night. It’s hard, but it’s very normal. You can’t force them to mature faster, but you can help them shift their sleep rhythms by keeping their nighttime environment very dark and peaceful, getting exposure to bright daylight first thing in the morning, and having them spend their days (including naps) in a noisy and well-lit environment. Try to wake them every 2-3 hours for a full feeding during the day so that they get used to allocating most of their calories to the daytime hours.
Newborn Sleep Pressure
Being awake, active, and alert builds sleep pressure over time. Sleep pressure is the brain’s need to sleep in order to replenish itself, flush toxins, form neural pathways, and process the information gathered while awake. This pressure builds very quickly for your newborn baby, whose brain is growing and building synapses at a breakneck pace.
Most newborns can handle 40-60 minutes awake before they need to sleep again. This time includes feeding, so don’t be surprised if all you can do is feed your baby and change their diaper before it’s time for a nap!
In the earliest weeks, your baby may be so sleepy that you have to work to keep them awake for a full feeding. Between 1 and 2 months old, this sleepy haze typically begins to wear off, and you’ll have to work to get them to sleep before they get overtired instead! Since they don’t have sleep hormone patterns yet, they rely on you to closely monitor their awake time and cue them that it’s sleeping time. Establishing a simple, predictable naptime routine and a safe, familiar sleep environment is a great way to start.
Newborn Sleep Patterns
Unlike a mature sleep cycle, which is typically about 90 minutes in length and includes four distinct stages, a newborn’s sleep cycle is just two stages, split evenly: “active” sleep (REM sleep) and “quiet” sleep (non-REM sleep). The duration of a newborn sleep cycle can be anywhere from 20 to 50 minutes.
During active sleep, they may be noisy, squirmy, and more easily awakened, so it’s helpful to pause and make sure they’re actually awake before you respond to their sounds (even fussing!). If you need to transfer them from your arms to another sleep space, it’s best to do so while they’re in quiet sleep.
Their sleep cycles will mature into four stages, resembling those of adults, between 3-5 months (often contributing to the infamous four-month sleep regression–but more on that another time!).
Thankfully, the chaos doesn’t last forever. Your sleepy, snuggly night owl will grow into a baby that reliably produces cortisol and melatonin, can stay awake and play longer than mere minutes, and cycles through longer and more predictable sleep stages. In the meantime, remember that you’re doing great, your baby is right on track, and it really does go by fast!
Author:
Hallie Liening is a firefighter's wife, mom to two little girls, and the owner and consultant at Sleep Bright. After navigating the depths of sleep deprivation and associated PPD, she was inspired to learn as much as she could about how babies sleep, and came to love the challenge of putting together sleep puzzles and helping families get their sanity back in the process! When she's not nerding out on baby sleep science or spending time with her family, you may find her taking dressage lessons, doing her at-home weightlifting routine, or studying the Bible. Photography, hot chocolate, and lively discussions about nearly anything are her love languages.