Thirteen Weeks!

Crown to rump length is 2.5-3 inches and weight is about .5 and .75 oz. It is about the size of a peach. The uterus fills the pelvis and is starting to grow upward into the abdomen. The baby has doubled in length from 7 weeks. There is a relative slowdown in the growth of the baby's head. Right now the head is about half of the crown to rump length. By birth the head is .25 size of the body. External genitalia have developed enough so male can be distinguished from female outside of the womb. Intestines initially develop within a large swelling in the umbilical cord outside the fetal body. About this time, they withdraw into the fetal abdominal cavity.