Medical Evaluation of Female Sexual Dysfunction

Susan E. Bennett

Shana L. Birnbaum

With advances in pharmaceutical treatment of male erectile dysfunction, there has been new attention focused on understanding female sexuality with the intent to develop treatments for what has been termed female sexual dysfunction (FSD).

PATHOPHYSIOLOGY AND CLINICAL PRESENTATION (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 and 18)

Sexual difficulties are highly prevalent, with some degree of erectile dysfunction reported among 52% of all men between 40 and 70 years of age. FSD, however, is harder to quantify and measure. The most widely quoted community-based survey, conducted in the United States in 1992, indicated that the prevalence of sexual problems among women is 43%. However, critics have questioned the terminology of this report, in which “difficulty” in any 2-month period was counted as a “dysfunction.” In addition, the women were not asked whether the problem was severe or significant enough to be a cause of personal distress. The most recent Kinsey Institute data indicate that physiologic measures of response during sexual activity were not predictive of a woman’s satisfaction with her sexual life, whereas emotional health and relationship factors, along with overall physical health, were predictive. Although exact diagnostic criteria for the disorders of FSD are being debated, there is consensus that the symptoms must cause distress to the woman to be indicative of sexual dysfunction.

Disorders of Sexual Desire

Low desire is the most common sexual problem reported by women, with prevalence rates ranging from 10% to 51% in various studies. In the Study of Women Across the Nation (SWAN), 40% of healthy midlife women reported that they rarely or never experienced spontaneous sexual desire. However, the majority of these women were satisfied with their sex lives. Aging, lengthier sexual relationship with the same partner, and loss of ovarian function correlate with lower desire. Because these are common experiences for the majority of women, low desire is not necessarily dysfunctional.

The Role of Sex Hormones

At issue has been the role of sex hormones in disorders of sexual desire. Responses to treatment have been informative. There is no evidence that hormone replacement with estrogen or progesterone improves sexual desire. In addition, when transdermal testosterone was administered to premenopausal women with decreased sexual satisfaction and low serum testosterone levels, the results were inconclusive. A large population study in Australia failed to show a correlation between androgen levels (total and free testosterone, dehydroepiandrosterone [DHEA] sulfate, and androstenedione) and self-reported sexual desire and sexual satisfaction. A randomized, placebo-controlled, and double-blinded trial of testosterone administered by a transdermal delivery
system showed significant improvement in the number of sexually satisfying events per month among women who were status/post total abdominal hysterectomy bilateral salpingo-oophorectomy before menopause and treated with estrogen replacement therapy; however, a strong placebo response diminished the significance of the outcome. Although a follow-up study of postmenopausal women not on estrogen replacement therapy demonstrated improved sexually satisfying events among women wearing testosterone transdermal patches, there was a small but significant increase in breast cancers in the treated group. These findings of a relatively small benefit and some increased cancer risk have discouraged U.S. Food and Drug Administration (FDA) approval of transdermal testosterone.

The Role of Sexual Desire in Seeking Sexual Activity

A recent and important interpretation of the evidence in this area holds that sexual desire is not the primary reason most women seek sexual activity, even if lack of desire is the most common reason women seek medical advice about their sexual health. Rosemary Basson argued that sexual desire follows arousal for many women, who are willing to accept sexual engagement with an intimate partner with the belief that desire and satisfaction will follow. The unisex linear sexual response cycle proposed by Masters and Johnson in 1966 and modified by Helen Kaplan in 1973 created the expectation that sexual desire is a prerequisite for a sexual encounter. Basson observed that this model does not reflect the sexual reality of many women.

Disorders of Sexual Arousal

Problems of arousal are less common than low sexual desire. In SWAN, 5% of women reported difficulties becoming sexually aroused. One of the problems with assessing the prevalence of arousal disorders is that most studies use vaginal lubrication as a marker of arousal. Genital arousal in men is penile erection, and in women, genital arousal is vaginal vasocongestion with associated lubrication. Subjective arousal is the physiologic state associated with perceived sexual excitement and the desire to seek continued sexual stimulation. Although there is a close relationship between penile erection and subjective arousal in men, there is a poor correlation between genital and subjective arousal in women. This may be among the reasons why sildenafil (marketed under the brand name Viagra) for women with the female sexual arousal disorder failed to show benefit.

Lack of subjective arousal for women is likely related to lack of clitoral stimulation and engorgement. The clitoris is widely believed to be a small structure, 1 cm in diameter and 2 cm in length. Autopsy dissections demonstrated that the clitoris is much larger, approximately 9 cm in length, with the majority of this complex structure inside the pelvis. Engorgement of the clitoris is obviously more difficult to measure than penile or vaginal engorgement, and this might explain the lack of correlation between genital and subjective arousal for women. In addition, sexual desire may result from or be dependent upon subjective arousal.

Disorders of Orgasm

Unlike male orgasm, there is no evidence that female orgasm is necessary for procreation. Adaptive evolutionary theory is that women have the erectile tissue and neurovascular connections for orgasm because the clitoris and penis arise from the same embryologic organ. A significant proportion of women do not experience orgasm with intercourse. A review of sexology literature found that 25% of women always experienced orgasms during sexual intercourse. Approximately one third of women rarely or never experienced orgasm during intercourse. The majority of women require direct clitoral stimulation to achieve orgasm during intercourse or masturbation. When asked to describe what parts of their genital anatomy required the least stimulation to achieve orgasm, women in one study uniformly reported that the area above and on top of the glans clitoris was more sensitive by far than any other area, including the vestibule and anywhere inside the vagina. A small proportion of women expel copious fluid at the time of orgasm, and this has been termed female ejaculation. Anatomically, there are no structures in the female genitalia large enough to contain more than a few millimeters of fluid other than the vagina and bladder. Thus, female ejaculation remains controversial.

Disorders Causing Sexual Pain

The prevalence of sexual pain disorders was reported to be 7% in the 1992 survey.

Dyspareunia is the sexual pain disorder most likely to be brought to the attention of the primary care clinician. Several mechanisms may be responsible for painful intercourse (Table 115-1), depending on whether the symptoms occur with initial insertion of the penis or deep penetration. Pain is experienced in the former case because of failure of lubrication or inadequate stimulation, vaginal or vulvar irritation, and structural impediments secondary to surgery, inflammation, or anatomic variants. Deep pain can arise from friction against inflamed tissue or by jarring of inflamed parametrial structures. The psychological contributions to dyspareunia reflect a variety of issues.

Pain on insertion can be caused by irritation of the vulva, which, in turn, is caused by multiple factors, including vulvovaginal infections (see Chapters 114 and 117). Ulcerative diseases like genital herpes commonly cause external pain with coitus, as do the vulvar dermatoses, including eczema, lichen planus, and lichen sclerosis. Irritation may be secondary to the use of scented soaps, shaving foam, spermicide, or a condom. A cyst of the Bartholin gland duct occurs when mechanical irritation and the attendant inflammatory reaction obstruct the ductal lumen, causing a painful cystic swelling in the vestibule. Irritation from a previous surgery, including an episiotomy, may also be responsible for pain.

Thin vulvar and vaginal mucosal tissue, as seen in estrogen deficiency, are less resilient and more susceptible to trauma. This type of vaginal atrophy is virtually universal among menopausal women, who may have insufficient lubrication even with adequate stimulation. Atrophic vaginitis is a common cause of dyspareunia. Similar symptoms and vaginal changes can be seen in any woman in a low-estrogen state, including women who are breast-feeding or postpartum, have anorexia or other causes of hypothalamic amenorrhea, or have had pelvic irradiation. In premenopausal women, inadequate lubrication due to insufficient foreplay is among the most frequent causes of dyspareunia. Medications may also contribute to vaginal dryness, including low-dose or progestinonly oral contraceptives. Finally, scant production of vaginal secretions may reflect inadequate arousal due to anxieties about sexual intercourse or risk of infection or relationship conflicts.

TABLE 115-1 Important Causes of Dyspareunia

Pain Greatest on Insertion	Pain Greatest on Deep Penetration
Inadequate lubrication	Pelvic inflammatory disease
Vaginitis	Ovarian cyst
Incompletely ruptured hymen	Endometriosis
Bartholin gland cyst	Pelvic adhesions
Stricture	Relaxation of pelvic support
Inadequate episiotomy	Uterine fibroids
Vulvovaginal atrophy
Genito-pelvic pain/penetration disorder

TABLE 115-2 Secondary Causes of Sexual Dysfunction

Medical	Social	Psychiatric
Cushing disease	Fatigue	Bipolar disorder
Addison disease	Chronic stress	Anxiety disorder
Diabetes mellitus	Lack of privacy	Major depression
Hypopituitarism	Relationship problems	Panic disorder
Hyperprolactinemia Degenerative joint disease Hypothyroidism Multiple sclerosis Temporal lobe lesions Coronary heart disease	Lack of partner	Somatization disorder Somatoform pain disorder