How do I tell the difference between a sleep regression and a growth spurt?

Since these two often overlap, it's very normal for you to be confused. Here's a rough way to tell them apart:

Growth spurt shows itself more through appetite: for 2-3 days your baby nurses or feeds noticeably more than usual, may fuss at the breast (because milk is coming slowly) but settles once satisfied. Sleep is sometimes disrupted because of increased hunger, but once fed, they fall back asleep easily.

Sleep regression mainly disrupts sleep rhythms: your baby struggles to fall asleep, wakes frequently, but isn't necessarily waking because they're hungry — sometimes they nurse a bit and go right back to sleep, sometimes they just want to be held or rocked. Appetite is normal, or only mildly elevated from lack of sleep.

Practical test: if your baby wakes at night, offer them a feed; if they nurse and fall asleep quickly afterward, lean toward growth spurt; if they refuse to nurse or nurse but stay awake, lean toward regression.

Both are normal parts of development and temporary (usually 2-6 days). But if the increased appetite lasts more than a week or your baby never seems satisfied, check in with your pediatrician about the weight-gain timeline.