Abnormal Bleeding

Menstrual irregularity is especially common in the perimenarchal and perimenopausal years. Bleeding from the vagina is considered abnormal when it occurs at an unexpected time of life (before menarche or after menopause) or varies from the norm in amount or pattern. Spontaneous abortions, pregnancy complications, and bleeding from polyps or other pathologic processes account for approximately 25% of the cases of abnormal vaginal bleeding.

Dysfunctional uterine bleeding is a confusing, nonspecific diagnostic term. It has been defined as abnormal uterine bleeding not due to structural or systemic disease. Therefore, this diagnosis may be reached only by a process of exclusion. It is almost always associated with anovulatory cycles. With advances in the understanding of the neuroendocrinologic basis of the menstrual cycle, diagnosis and therapy have become more specific (see Selected References).

To understand and diagnose the various causes of menstrual irregularities, the examiner must have a thorough knowledge of normal physiology (Fig. 20-1). Although the history is important, it is seldom diagnostic and serves only as a guide to the origin of the bleeding. In most patients, hormonal or cytologic studies are necessary to establish the correct diagnosis.

Figure 20-1 Normal menstrual cycle, with pituitary anatomy and levels of gonadotropins, ovarian activity and levels of ovarian steroids, and changes in endometrium. GnRH, gonadotropin-releasing hormone.

(From Braverman PK, Sondheimer SJ: Menstrual disorders. Pediatr Rev 18:18, 1997. Illustration by Marcia Smith.)

Nature of Patient

Before menarche, a characteristic sequence of events begins at about age 8 years (Fig. 20-2). Breast buds develop, pubic hairs appear, breasts enlarge, axillary hairs appear, and finally a height spurt occurs. Menstrual function usually begins after the height spurt. About 6 months before menarche, physiologic leukorrhea occurs. In the first year after menarche, 55% of menses are anovulatory, with a sharp decline to about 7% by 8 years after menarche. Usually, 15 months is required for completion of the first 10 menstrual cycles. This means that when menses begin, it is unusual for them to occur at regular monthly intervals.

Figure 20-2 Relationship of pubertal events in adolescent girls.

(From Lopez RI: Menstrual irregularities in teenage girls. Drug Ther April:49, 1981.)

The average age at which girls begin to menstruate is 12 years. Table 20-3 shows the characteristics of normal menstruation. Bleeding that occurs before 9 to 10 years of age is abnormal, and local pathology as well as adrenal and ovarian tumors must be suspected. Because some teenage girls are reluctant to volunteer information about their menstrual periods, it is essential that physicians routinely ask a series of questions, as follows:

TABLE 20-3 Characteristics of Menstruation^∗

^∗ Range and averages for American women.

These questions must be asked in a nonthreatening way so that the patient feels at ease and understands that the physician is willing to listen. Likewise, when asking questions about sexual activities, the physician must remain nonjudgmental. The teenager should be reassured that any discussion of this nature will remain a private matter between patient and physician.

The adolescent typically has cycles of variable length. Anovulation may be associated with both short and long cycles together with short follicular and luteal cycles. Menarche may be delayed in underweight adolescents as well as in some teenage girls who are on strict diets to remain fashionably thin and in athletes with normal body weight but low body fat. Menarche often has a familial pattern; girls often start menstruating at about the same age as their mothers and older sisters did.

Several significant age-associated conditions can cause abnormal vaginal bleeding. In children, insertion of foreign bodies into the vagina may cause bleeding.

In adolescence, amenorrhea, dysmenorrhea and abnormal uterine bleeding are common, affecting about 75% of adolescents. Both primary and secondary amenorrhea can occur. When pelvic anatomy and ovarian function are normal, dysmenorrhea is considered primarySecondary dysmenorrhea occurs when dysmenorrhea is associated with pelvic or hormonal pathology. In adolescents, anovulation causes virtually all instances of dysfunctional uterine bleeding and 90% of all instances of abnormal uterine bleeding.

During the reproductive years, dysfunctional uterine bleeding and bleeding from pregnancy complications, tumors, or fibroids may occur (Table 20-4). A menstruating woman of any age can bleed from complications of pregnancy. Anovulatory estrogen-withdrawal bleeding is the most common cause of irregular menses during the reproductive and perimenopausal years, accounting for 40% of menstrual disturbances in the perimenopausal years.

TABLE 20-4 Causes of Vaginal Bleeding in the Reproductive Years

Other, less common causes of abnormal vaginal bleeding in perimenopausal women are organic lesions (neoplasm or inflammatory diseases of the cervix, vagina, and endometrium), constitutional diseases (hypothyroidism, hyperthyroidism, Cushing’s disease, cirrhosis, thrombocytopenia), and certain drugs (Table 20-5). In postmenopausal women, bleeding may result from endometrial and cervical cancers.

TABLE 20-5 Common Drugs That May Alter Menstrual Bleeding

∗ May also produce galactorrhea.