Sleep regressions: what is known, and what is not

Around 4 months

This is the age with a medical source behind it. The AAP says babies don't have regular sleep cycles until about 4 months. After that, it advises putting babies to bed drowsy but not asleep, so they learn to fall asleep on their own and can settle themselves if they wake.

Whether this change feels like a "regression" to a family is a different question, and the AAP page doesn't use that word.

Around 8 to 10, 12 and 18 months: the evidence is thin

The idea that sleep gets worse for a few weeks at these ages comes from parenting books and websites. We did not find a pediatric or public-health page that defines these as stages, gives their length, or says what causes them, so we do not give a length or a cause.

What the AAP does say is that waking in the night is common and that children need time to learn to fall back asleep on their own.

What the AAP suggests when sleep is hard

• Keep the same calm routine and bedtime each night (see bedtime routines).
• Keep night feeds and diaper changes calm and quiet, and don't stimulate your baby.
• Give your baby a moment to settle before you step in; babies need time to learn to settle themselves.
• Be patient: the AAP says sleep changes take time.

Safe sleep does not change

A hard stretch is never a reason to change where or how your baby sleeps: on the back, alone, in a crib or bassinet, for every sleep. Please read the safe sleep page.