Healthy newborns follow a comfortable pattern. They're up two or three times a night for food and comfort, but you expect these nocturnal disturbances with a new baby.

But at three or four months of age, everything changes. Your baby now wakes at all hours of the night, and exhaustion and frustration become the norm.

The good news is you haven't done anything wrong. Your baby's new sleep pattern (or lack thereof) is a biological response known as the four-month regression.

Infant sleep experts Meg Casano, BSN, MA, and Erin Flynn-Evans, PhD, MPH, provide the knowledge and strategies you need to get through the four-month regression and reestablish restful sleep patterns. Unlike many misleading and uninformed sleep "experts," Flynn-Evans and Casano base their advice on sound scientific principles so that you can act with confidence.

You'll discover how to spot early signs of the four-month regression, how to prevent it if possible, and how to resolve the issue if not. Doing so provides you with realistic expectations of your child's nighttime sleeping patterns and helps you guide your baby back to a healthy, restful nighttime routine.