The 4-Month Sleep Regression: What It Is and How to Survive It

If you're reading this at 3 AM while bouncing a crying baby, take a deep breath. You are not alone, and you are not doing anything wrong. The 4-month sleep regression is one of the most common—and challenging—phases of early parenthood.

What exactly is a sleep regression?

Despite the name, a sleep regression is actually a progression. Around 3 to 4 months of age, your baby's sleep cycles permanently change from newborn sleep patterns to adult-like sleep patterns. They now cycle through light and deep sleep, meaning they wake up slightly between cycles. If they don't know how to fall back asleep independently, they cry out for you.

Signs your baby is going through it

• Increased fussiness and crying.
• Multiple night wakings (often every 1-2 hours).
• Shorter naps or refusing to nap altogether.
• Changes in appetite.

How to survive it

1. Practice putting baby down drowsy but awake. This is the golden rule of sleep training. It teaches them to fall asleep in their crib, so when they wake up between sleep cycles, they aren't alarmed by their surroundings.

2. Pay attention to wake windows. An overtired baby produces cortisol, which acts like adrenaline. At 4 months, wake windows should be around 1.5 to 2 hours.

3. Track the data. It's hard to see patterns when you're sleep-deprived. By tracking sleep, you can identify their natural rhythms and anticipate when they need to go down.