Pregnancy and uterine fibroids are two medical diseases that can cause the uterus to grow in size. As your uterus grows larger, you may feel a weight in your lower belly or observe your abdomen bulging. However, you may not have any obvious symptoms. Being pregnant when you have large fibroids can cause pain, bleeding, and infection. The only way to find out if this is happening to you is by having an ultrasound exam. Uterus size varies between women. In fact, the average uterus is 32-36 grams (1-1.4 oz). A uterus that is too small is a common problem for older women; they may experience difficulties with fertility or menstrual problems. Women with small uteruses often require hormone therapy to regulate their periods or delay menopause. Women with large uteri also experience problems such as infertility or excessive bleeding during menstruation. In some cases, surgery can be done to remove part of the stomach or intestines and fuse them directly to the uterus as a treatment for heavy menstrual bleeding or uterine fibroids. Women with very large uteruses (more than 100 grams or 3.5 ounces) may experience difficulty giving birth. The baby's head may not fit through the cervix, and there may not be enough room in the pelvis for the baby's shoulders and hips. This condition is called occipitocervical disproportion.