So, while it’s a physical and mental challenge for the whole family, a sleep regression is a good thing and a clear sign your baby is moving forward developmentally. Dr. Harvey Karp, founder of Happiest Baby, Pediatrician, and author, tells me sleep regressions are a normal part of childhood development: “A lot of times, this type of sleep disruption coincides with big jumps they’re making in terms of motor or mental advances.”