If you're reading this at 3 a.m. wondering why your baby thinks midnight is party time, you're not doing anything wrong -- and you're definitely not alone. Newborn sleep is weird, choppy, and completely unlike ours, for reasons that actually make a lot of sense once you know them.
Newborns Don't Have a Circadian Rhythm Yet: The internal clock that tells us when to sleep and wake -- the circadian rhythm -- takes about 3 to 4 months to develop. Until then, your baby has no concept of day vs. night.
Newborn Sleep Cycles Are Shorter: Adult sleep cycles run about 90 minutes. Newborn sleep cycles are roughly 50 to 60 minutes, and they spend a much larger portion of that time in active (REM) sleep -- the light, easily-disrupted stage.
Wake Windows Are Tiny: Newborns can only stay awake for 45 to 90 minutes before they need to sleep again. Keeping them up longer doesn't help them sleep better at night -- it usually makes things worse by creating overtiredness.
Normal Newborn Night Sleep: Most newborns sleep in 2 to 4 hour stretches, waking to feed. Sleeping "through the night" (a 5 to 6 hour stretch) typically doesn't happen until 3 to 6 months, and often later.
Quick Takeaways: No circadian rhythm until 3-4 months. Sleep cycles are 50-60 minutes. Wake windows are only 45-90 minutes. Night stretches of 2-4 hours are completely normal.
