At 12 weeks pregnant, a mother's uterus has grown to the height of her belly button, making the pregnancy noticeable for the first time, according to Johns Hopkins Medicine. The skin of the belly also continues to grow and may even begin to feel itchy at times.
At 12 weeks, often referred to as the second trimester, a woman's uterus is continually growing and stretching, notes Johns Hopkins Medicine. This may cause pain along the sides of a woman's body. Additionally, ligaments in the lower abdomen begin stretching to accommodate the growing uterus, which may also cause abdominal pain. However, many women find that the persistent need to urinate disappears at this point. This is because, as the uterus is growing, it is rising out of the pelvic cavity. The uterus can also be felt through the abdominal wall for the first time.
A mother may experience changes in the rest of her body at this point as well, adds Johns Hopkins Medicine. For example, a mother's skin pigmentation may change on her face and belly as the pregnancy continues. Also, a mother's nose may begin to feel congested, and she may have nosebleeds. This is because of the increase in estrogen and progesterone in the woman's body. These same hormones may also cause a woman's gums to become spongy and bleed.