In a typical pregnancy that lasts 40 weeks, the 20th week of fetal growth signifies that the pregnancy is halfway over. This may or may not be true as the typical length of a normal pregnancy is anywhere from 38 to 42 weeks long. Your baby is truly beginning to behave like a newborn. She is establishing sleep patterns, and she is probably awake as often as she will be in the first few weeks after birth. If your baby is a girl, her uterus is developing. Hair folicles are also beginning to grow hair during this month.