Skip to Main Content


ED visits for vaginal bleeding by women of reproductive age are common. Menorrhagia occurs in 9% to 14% of healthy women, although most will have a normal duration of menses. An estimated 5% of women aged 30 to 49 years old will consult a physician for treatment alterations in pattern or volume of flow of menses. The focus of this chapter is on excessive or prolonged bleeding rather than oligomenorrhea or amenorrhea.


To understand abnormal uterine bleeding, it is necessary to define normal menstrual flow. The mean interval between menses is 28 days (±7 days). The mean duration of menstrual flow is 4 days, with most blood loss occurring in the first 2 days. For practical purposes, a change in the duration of flow is abnormal, even though by definition, a woman may not have menorrhagia (Table 99-1).

Table Graphic Jump Location
Table 99-1 Definitions Related to Vaginal Bleeding 

Normal Menstrual Cycle


The lower age limit for menarche tends to be 10 years old, and the mean age in North America is 12.5 years. Most girls develop secondary breast changes 2 years before the onset of menarche. At the time of ovarian stimulation, a white or yellow vaginal discharge, which is both nonodorous and nonirritating, may appear. Early cycles are anovulatory and irregular, but unlike adult anovulatory cycles, bleeding is generally not excessive. The hypothalamic pituitary axis takes 1 to 5 years to reach full maturity, and the average time to establish ovulatory cycles is 2 years after menarche.


The normal menstrual cycle is 28 days and is divided into four phases: menses, follicular, ovulation, and luteal or secretory. The first day of the cycle corresponds to the first day of menses, which generally lasts 4 days and involves the sloughing of the functionalis layer of the endometrium. The interval from day 5 through day 14 is the follicular (proliferation) phase, during which the ovary matures an oocyte for ovulation, and the granulosa cells, lining the follicle, produce estrogen. This stimulates the endometrium to proliferate and thicken (Figure 99-1).

Figure 99-1.
Graphic Jump Location

The hormonal, ovarian, endometrial, and basal body temperature changes and relationships throughout the normal menstrual cycle. E2 = prostaglandin E2; FSH = follicle-stimulating hormone; ...

Want remote access to your institution's subscription?

Sign in to your MyAccess profile while you are actively authenticated on this site via your institution (you will be able to verify this by looking at the top right corner of the screen - if you see your institution's name, you are authenticated). Once logged in to your MyAccess profile, you will be able to access your institution's subscription for 90 days from any location. You must be logged in while authenticated at least once every 90 days to maintain this remote access.


About MyAccess

If your institution subscribes to this resource, and you don't have a MyAccess profile, please contact your library's reference desk for information on how to gain access to this resource from off-campus.

Subscription Options

AccessMedicine Full Site: One-Year Subscription

Connect to the full suite of AccessMedicine content and resources including more than 250 examination and procedural videos, patient safety modules, an extensive drug database, Q&A, Case Files, and more.

$995 USD
Buy Now

Pay Per View: Timed Access to all of AccessMedicine

24 Hour Subscription $34.95

Buy Now

48 Hour Subscription $54.95

Buy Now

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.