| Approximately 10% of DUB results from anovulation, and 90% occur with ovulatory cycles. |
| In ovulatory DUB, prolonged progesterone secretion causes irregular shedding of the endometrium. This probably is related to a constant low level of estrogen that is around the bleeding threshold. This causes portions of the endometrium to degenerate and results in spotting. |
| Obese females tend to have irregularities in their menstrual cycles due to nonovarian endogenous production of estrogen often related to their degree of adipose tissue. This usually results in prolonged cycles of amenorrhea that alternate with cycles of metrorrhagia or menometrorrhagia. |
| Although, DUB in itself is rarely fatal, distinguishing this presentation from that of endometrial cancer is important. Development of endometrial cancer is related to estrogen stimulation and endometrial hyperplasia. Symptoms include postmenopausal bleeding, which is usually considered cancer until proven otherwise. |
| DUB is most common at the extreme ages of a woman's reproductive years, either at the beginning or near the end, but it may occur at any time during her reproductive life. |