Sleep regressions, decoded

Regressions aren't failure — they're developmental leaps that temporarily disrupt sleep. The 4-month one is a permanent maturation of sleep architecture (baby now cycles through lighter phases and briefly wakes between them). It's really a progression, misnamed. The 8-month wobble is driven by separation anxiety peaking — baby now knows you exist even when they can't see you, and prefers you present. The 12-month one usually correlates with walking, first words, and molar teething. Stay consistent with the routine. Don't introduce new sleep crutches you can't sustain long-term. Most regressions resolve within 2–4 weeks. If everyone is exhausted, the 4-month window is a common time to consider a structured sleep approach.