By 29 to 30 weeks, a growing baby has matured a lot. Premature babies born between 29 and 30 weeks will still require long NICU stays, but their vital organs are much more developed than those of babies born earlier.
By 29 to 30 weeks, premature babies weigh about 3 pounds and are about 17 inches long. Although they're still very small, 29 weekers and 30 weekers have more fat stored under their skin, so they look more like "real" babies. They are starting to shed their lanugo, the fine hair that covers a preemie's body.
In addition to all of this outside maturity, the brain goes through a period of rapid growth as well. The brains of 29- and 30-week premature babies are starting to look grooved and wrinkled, and are mature enough to begin controlling body temperature.