The uterus is a hollow organ about the size and shape of an upside down pear. In the average woman, it's positioned forward, above the bladder. But on occasion, it may be tilted or 'tipped' backward, or otherwise be out of alignment. In most cases, the tipped uterus is simply a normal variation. Unless pain, bleeding or other symptoms result, no treatment is needed. During pregnancy, a tilted uterus will temporarily become upright, and then return to its regular position after childbirth. Contrary to past belief, a tipped uterus does not cause miscarriage or infertility. The uterus tends to be somewhat mobile, and may shift around temporarily as a result of physical activity. But occasionally, displacement of the uterus is the result of a pelvic disease, which requires separate treatment. When the uterus is abnormally positioned due to endometriosis (en-doe-mee-treE-OH-sis), it often causes lower back pain, just before and during the menstrual period. You should be aware that a tipped uterus is not the same as uterine prolapse. In prolapse, the uterus begins to sag down into the vagina, due to weakened ligaments or pelvic floor muscles. To make sure any changes in the uterus are monitored, it's important to get regular pelvic exams, and mention any unusual symptoms to a doctor. For more information on a tipped uterus, consult a health care provider.