Baby Sleep Regressions: What's Normal vs What's Not

A baby sleep regression is a period where sleep temporarily becomes more disrupted after a phase of relative improvement. These regressions often feel sudden and exhausting, especially when parents believe they have done something wrong. In reality, sleep regressions are a normal part of infant development and are closely linked to neurological and physical growth.

Common regression periods tend to occur around four months, six to eight months, eight to ten months, and again around twelve months. Each of these stages corresponds with significant developmental changes, such as the maturation of sleep cycles, increased mobility, separation awareness, and cognitive leaps.

The four-month regression is often the most challenging because it marks a permanent change in how babies sleep. At this age, sleep cycles mature and become more similar to adult sleep architecture, which means babies experience lighter sleep more frequently.

Supporting a baby through a regression involves maintaining a calm bedtime routine, avoiding overtiredness, and responding in ways that feel sustainable for the family. Progress during these periods is rarely linear, and setbacks are not failures.