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Dysmenorrhea; Menorrhagia; Amenorrhea; Cramps; Heavy menstrual bleeding
Reproductive Hormones. The hypothalamus (an area in the brain) and the pituitary gland control the reproductive hormones. In women, six hormones help regulate the reproductive system:
Ovulation is the process where a mature egg (ovum) is released from the ovary. The egg begins its development inside a follicle of the ovary:
LH serves two important roles:
The so-called "fertile window" is 6 days long and starts 5 days before ovulation and ends the day of ovulation. Fertilization occurs as follows:
If the egg is not fertilized, the corpus luteum degenerates into a form called the corpus albicans, and estrogen and progesterone levels drop. Finally, the endometrial lining sloughs off and is shed during menstruation.
Typical Menstrual Cycle
Typical No. of Days
Follicular (Proliferative) Phase
Cycle Days 1 through 6: Beginning of menstruation to end of blood flow.
Estrogen and progesterone start out at their lowest levels.
FSH levels rise to stimulate maturity of follicles. Ovaries start producing estrogen and levels rise, while progesterone remains low.
Cycle Days 7 - 13: The endometrium thickens to prepare for the egg implantation.
Cycle Day 14:
Surge in LH. Largest follicle bursts and releases egg into fallopian tube.
Luteal (Secretory) Phase, also known as the Premenstrual Phase
Cycle Days 15 - 28:
Ruptured follicle develops into corpus luteum, which produces progesterone. Progesterone and estrogen stimulate blanket of blood vessels to prepare for egg implantation.
If fertilization occurs:
Fertilized egg attaches to blanket of blood vessels that supplies nutrients for the developing placenta. Corpus luteum continues to produce estrogen and progesterone.
If fertilization does not occur:
Corpus luteum deteriorates. Estrogen and progesterone levels drop. The blood vessel lining sloughs off, and menstruation begins.
What is Menstruation? Menstruation, also called a "period," is the cyclical flow of blood from the uterus in women between puberty and menopause.
Onset of Menstruation (Menarche). The onset of menstruation, called the menarche, typically begins between the ages of 12 - 13 years. Menarche generally occurs 2 - 3 years after initial breast development (breast budding). African-American and Hispanic girls tend to mature slightly earlier than Caucasian girls. A higher body mass index (BMI) during childhood is associated with an earlier onset of puberty. Environmental factors and nutrition may also affect menarche timing.
Length of Monthly Cycle. The menstrual cycle can be very irregular during the first 1 - 2 years, ranging from 21 - 45 days. The length then generally stabilizes to an average of 28 days, although the cycle length may range from 21 - 35 days and still be considered normal. A variation of 10 days or more -- either more or fewer days -- may have an impact on fertility, however. The cycle lengthens when a woman is in her 40s, reaching an average of 31 days by age 49. A number of factors can affect cycle length at any age.
Risk Factors for Shorter and Longer Cycles
Regular alcohol use.
Being under 21 and over 44.
Being very thin (also at risk for short bleeding periods).
Competitive athletics (also at risk for short bleeding periods).
Length of Periods. Periods average 6.6 days in adolescent girls. By the age of 21, menstrual bleeding averages 6 days until women approach menopause. However, about 5% of healthy women menstruate fewer than 4 days and 5% menstruate more than 8 days.
Normal Absence of Menstruation. Normal absence of periods can occur in any woman under the following circumstances:
American Academy of Pediatrics Committee on Adolescence; American College of Obstetricians and Gynecologists Committee on Adolescent Health Care; Diaz A, Laufer MR, Breech LL. Menstruation in girls and adolescents: using the menstrual cycle as a vital sign. Pediatrics. 2006 Nov;118(5):2245-50.
Apgar BS, Kaufman AH, George-Nwogu U, Kittendorf A. Treatment of menorrhagia. Am Fam Physician. 2007 Jun 15;75(12):1813-9.
Beaumont H, Augood C, Duckitt K, Lethaby A. Danazol for heavy menstrual bleeding. Cochrane Database Syst Rev. 2007 Jul 18;(3):CD001017.
Casablanca Y. Management of dysfunctional uterine bleeding. Obstet Gynecol Clin North Am. 2008 Jun;35(2):219-34.
Chen EC, Danis PG, Tweed E. Clinical inquiries. Menstrual disturbances in perimenopausal women: what's best? J Fam Pract. 2009 Jun;58(6):E3.
Damlo S. ACOG guidelines on endometrial ablation. Am Fam Physician. 2008 Feb 15;77(4):545-549.
Dietrich JE. Von Willebrand's disease. J Pediatr Adolesc Gynecol. 2007 Jun;20(3):153-5.
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 May;113(5):1104-16.
Lethaby A, Irvine G, Cameron I. Cyclical progestogens for heavy menstrual bleeding. Cochrane Database Syst Rev. 2008 Jan 23;(1):CD001016.
Lobo RA. Abnormal uterine bleeding. Ovalutory and anovulatory dysfunctional uterine bleeding, management of acute and chronic excessive bleeding. In: Katz VL, Lobo RA, Lentz G, Gershenson D, eds. Comprehensive Gynecology. 5th ed. St. Louis, MO: Mosby; 2007:chap 37.
Lobo RA. Primary and secondary amenorrhea and precocious puberty. Etiology, diagnostic evaluation, management. In: Katz VL, Lobo RA, Lentz G, Gershenson D, eds. Comprehensive Gynecology. 5th ed. St. Louis, MO: Mosby; 2007:chap 38.
Master-Hunter T, Heiman DL. Amenorrhea: evaluation and treatment. Am Fam Physician. 2006 Apr 15;73(8):1374-82.
Ortiz DD. Chronic pelvic pain in women. Am Fam Physician. 2008 Jun 1;77(11):1535-42.
Practice Committee of American Society for Reproductive Medicine. Indications and options for endometrial ablation. Fertil Steril. 2008 Nov;90(5 Suppl):S236-40.
Proctor ML, Farquhar CM. Dysmenorrhoea. Clin Evid. 2006 Jun;(15):2429-48.
Sambrook AM, Bain C, Parkin DE, Cooper KG. A randomised comparison of microwave endometrial ablation with transcervical resection of the endometrium: follow up at a minimum of 10 years. BJOG. 2009 Jul;116(8):1033-7. Epub 2009 May 11.
Witt CM, Reinhold T, Brinkhaus B, Roll S, Jena S, Willich SN. Acupuncture in patients with dysmenorrhea: a randomized study on clinical effectiveness and cost-effectiveness in usual care. Am J Obstet Gynecol. 2008 Feb;198(2):166.e1-8.
Wong CL, Farquhar C, Roberts H, Proctor M. Oral contraceptive pill as treatment for primary dysmenorrhoea. Cochrane Database Syst Rev. 2009 Apr 15;(2):CD002120.
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