The dreaded 4-month sleep regression is the time when your baby’s sleep patterns shift and they wake up often during the night and refuse to go back to sleep.

The 4-month sleep regression is when a baby experiences sleeping difficulty at 4-months-old. Research into this is limited, and not all babies will experience it.

Sleep is precious (and sometimes hard to come by) in the first year of your baby's life. Here's how to make it through the 6-month sleep regression.

From 4 months to about 1 year of age, they'll sleep 9 to 12 hours at night, with a couple added naps during the day. But remember, most babies will sleep only about 5 to 6 hours at a time to start.

“Sleep training is safe around 4 months when children are able to start to self-soothe,” says Dr. Scott Cohen of Beverly Hills Pediatrics, and author of “Eat, Sleep, Poop.” ...

Babies get less sleep at night and sleep for shorter stretches when they sleep in their parents' room after 4 months old, a new study finds. Daniela Jovanovska-Hristovska/Getty Images hide caption ...

Babies as young as 2 months old can be taught to sleep through the night by being left to cry, says a large and prominent pediatrics practice in New York and Los Angeles.

Is your 4-month-old suddenly not sleeping as well? Here's how long sleep regressions last and why they happen.