According to Baby Center, the uterus returns to its pre-pregnancy size and shape about four weeks after a woman gives birth. Even after the uterus resumes its normal size, the woman's abdomen may protrude slightly because the abdominal muscles have stretched during pregnancy. More time and regular exercise are needed to return the muscles to their previous tone.
During pregnancy, the uterus weighs about 15 times more than it does before a woman conceives, and its volume increases by over 500 percent, Baby Center explains. Within a few minutes of delivery, uterine contractions begin the process of separating the placenta from the uterine wall. After the placenta is delivered, these contractions continue, closing off the open blood vessels where the placenta was attached. This typically causes cramps, which are referred to as afterpains. Bleeding and vaginal discharge also occur during this time. Known as lochia, this discharge consists of blood, bacteria and uterine tissue and typically lasts a month or more. At first it is bright red, but after several days it becomes pink-tinged and watery as bleeding subsides.
Web MD recommends that women take ibuprofen after delivering a baby to help with the muscle soreness, cramping and vaginal tenderness that occur. Ice packs may help decrease pain and swelling around the vaginal opening. Women are advised to refrain from sexual intercourse and avoid traveling long distances until their doctor approves, usually in about six weeks.