The uterus is the most instrumental part of the body when it comes to growing and delivering a newborn baby, and a pregnancy causes many changes in the organ. A woman's uterus enlarges and changes during pregnancy to accommodate and support the growing fetus. Directly following birth, the postpartum uterus begins to return to its normal pre-pregnancy size and condition. It squeezes and contracts as it shrinks. The postpartum uterus also sheds lochia, a discharge of blood and fluids that begins immediately after delivery and often continues for several weeks.
By the ninth month of pregnancy, a woman's uterus has grown to be about five times its normal size. A mother carrying multiples—two or more babies—may experience an even greater increase in the size of her uterus. This considerable change in height, length, depth, and overall shape allows the organ to accommodate one or more full-term babies, as well as the placenta, membranes, and amniotic fluid. The birth of the baby followed by the placenta triggers the postpartum uterus to begin shrinking. After one week, the size of the uterus has been reduced by half, and by six weeks, it has generally returned to its normal, pre-pregnancy measurements.
Another normal characteristic of the postpartum uterus is the release of blood, mucus, and other various fluids. When the placenta detaches from the uterine wall, it leaves an open wound that bleeds into the uterus. This process causes lochia to be heavy and bright red during the immediate postpartum period. Postpartum bleeding will likely continue for about six weeks after the birth, and a woman most commonly observes a change in color and flow as the bleeding subsides and the site of the detached placenta heals.
A Cesarean birth, where the baby is surgically removed through an incision in the uterus, can result in additional challenges. Cutting through the uterus results in more blood loss than a vaginal delivery, and stitches are required to close the wound and prepare it for healing. Recovering from a Cesarean section can be difficult, and women who experience fever, redness around the incision, and abnormal pain or discomfort, should contact a medical professional. A health care provider can determine whether a new mother experiencing such symptoms is suffering from an infection of the postpartum uterus.
A woman who has just given birth will likely have the condition of her uterus monitored by her team of health care providers. Nurses or midwives often massage the organ, encouraging it to contract and begin returning to its normal size. If the doctor or midwife observes a sluggish response in the postpartum uterus combined with an excessive amount of bleeding, medications may be administered. In rare cases, surgery may be required to stop the bleeding.