At the 13th week of pregnancy, the uterus fills the pelvis and starts to grow upward into the abdomen. WedMD explains that the uterus feels like a soft, smooth ball at this stage.
BabyCenter reveals that at the 13th week of pregnancy, the risk of miscarriage is lower than in early pregnancy. The baby weighs one ounce at this point and is about three inches long, approximately the size of a pea pod. The baby's head is relatively large, making up one-third of the baby's size. Fingerprints are formed on the fingers, and veins and organs are visible through the baby's skin. If the baby is a girl, her ovaries are formed and contain over two million eggs. WebMD reveals that the baby's eyes are in position and its wrists and ankles are formed.