Every woman's menstrual cycle, or period, is different.
On average, a woman's period occurs every 28 days.
Most women have cycles between 24 and 34 days apart. It usually lasts 4 to 7 days.
Young girls may get their periods anywhere from 21 to 45 days or more apart.
Women in their 40s will often notice their period occurring less often.
About every month, the levels of female hormones in a woman's body rise and fall. Estrogen and progesterone are two hormones that play an important role in ovulation. This is the time when the ovaries release an egg.
Dysfunctional uterine bleeding most commonly occurs when the ovaries do not release an egg. Changes in hormone levels cause your period to be later or earlier and sometimes heavier than normal.
Symptoms of dysfunctional uterine bleeding may include:
Bleeding or spotting from the vagina between periods
Periods that occur less than 28 days apart (more common) or more than 35 days apart
Time between periods changes each month
Heavier bleeding (such as passing large clots, needing to change protection during the night, soaking through a sanitary pad or tampon every hour for 2 to 3 hours in a row)
Bleeding that lasts for more days than normal or for more than 7 days
Other symptoms caused by changes in hormone levels may include:
Excessive growth of body hair in a male pattern (hirsutism)
Tenderness and dryness of the vagina
A woman may feel tired or fatigued if she is loses too much blood over time. This is a symptom of anemia.
Exams and Tests
Your health care provider will do a pelvic exam and may do a Pap test. Other tests that may be done include:
Call your health care provider if you have unusual vaginal bleeding.
ACOG Practice Bulletin No. 110: Noncontraceptive uses of hormonal contraceptives. Obstet Gynecol. 2010 Jan;115(1):206-18. PMID: 20027071 Available at: www.ncbi.nlm.nih.gov/pubmed/20027071.
Committee on Practice Bulletins - Gynecology. Practice bulletin no. 136: management of abnormal uterine bleeding associated with ovulatory dysfunction. Obstet Gynecol. 2013 Jul;122(1):176-85. PMID: 23787936 Available at: www.ncbi.nlm.nih.gov/pubmed/23787936.
Kaunitz AM, Meredith S, Inki P, Kubba A, Sanchez-Ramos L. Levonorgestrel-releasing intrauterine system and endometrial ablation in heavy menstrual bleeding: a systematic review and meta-analysis. Obstet Gynecol. 2009;113:1104-1116. PMID: 19384127 Available at: www.ncbi.nlm.nih.gov/pubmed/19384127.
Middleton LJ, Champaneria R, Daniels JP, Bhattacharya S, Cooper KG, Hilken NH, et al. Hysterectomy, endometrial destruction, and levonorgestrel releasing intrauterine system (Mirena) for heavy menstrual bleeding: systematic review and meta-analysis of data from individual patients. BMJ. 2010 Aug 16;341:c3929. PMID: 20713583 Available at: www.ncbi.nlm.nih.gov/pubmed/20713583.
Irina Burd, MD, PhD, Assistant Professor of Gynecology and Obstetrics at Johns Hopkins University School of Medicine, Baltimore, MD. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.