Variables Affecting Female Sexual Function

Sexuality for women extends far beyond the release of neurotransmitters, the influence of sex hormones, and vasocongestion of the genitals. A number of psychological and sociological variables may affect female sexual function, as may the aging process, menopause, the presence of diseases, and the use of certain medications.

Effect of Psychosocial Variables on Female Sexual Response

Among the psychosocial variables, perhaps the most important is the relationship with the sexual partner. John Bancroft, MD, and colleagues at the Kinsey Institute for Research in Sex, Gender, and Reproduction suggest that a reduction in libido or sexual response may actually be an adaptive response to a woman's relationship or life problems (rather than a disorder).⁽¹⁾ According to Basson, emotions and thoughts have a stronger impact on a woman's assessment of whether or not she is aroused than does genital congestion. ⁽²⁾

Other emotional factors that may have an impact on female sexual functioning are listed in Table 2.

TABLE 2. Psychological Factors Affecting Female Sexual Function

• Relationship with sexual partner
• Past negative sexual experiences or sexual abuse
• Low sexual self-image
• Poor body image
• Lack of feeling of safety
• Negative emotions associated with arousal
• Stress
• Fatigue
• Depression or anxiety disorders

Effects of Aging on Female Sexual Response

Contrary to popular belief, aging does not mean the end of sexual interest, particularly today when many men and women are coupling, uncoupling, and recoupling again, leading to renewed interest in sex due to the novelty of a new sexual partner. Many older women find themselves at a psychologically satisfying sexual peak because of their maturity, knowledge of their body and its workings, ability to ask for and accept pleasure, and their greater comfort with themselves.⁽³⁾

In the past, much of our information about sexuality at perimenopause and beyond has been based on anecdotal complaints from a small, self-selecting group of symptomatic women who presented to providers.^(4,5) Today we have large population-based studies that offer a more accurate picture.^(5,7)

Although many studies do show that there is a normative, gradual decline in sexual desire and activity with age, research also indicates that the majority of men and women who are healthy and have partners will remain interested in sex and engage in sexual activity well into midlife, later life, and until the end of life.⁽⁵⁾ An informal survey conducted by the consumer magazine More of 1,328 readers of the magazine (which is targeted to women over age 40) bears out this new thinking: 53 percent of women in their 50s said their sex life was more satisfying than it was in their 20s; 45 percent said they use vibrators and sex toys; and 45 percent would like a medication for women that enhances sexual desire and activity.⁽⁸⁾

Several factors appear to affect the ability to continue to be sexually active, most notably the availability of a willing sexual partner and a woman's health status (including the presence of a sexual disorder). The Duke Longitudinal Study of 261 white men and 241 white women between the ages of 46 and 71 found that sexual interest declined significantly among men because they were unable to perform (40 percent).^(7,9,10) For women, sexual activity declined because of the death or illness of a spouse (36 percent and 20 percent, respectively), or because the spouse was unable to perform sexually (18 percent). Regression analysis showed that age was the primary factor leading to a reduction in sexual interest, enjoyment, and frequency of intercourse among men, followed by present health. For women, marital status was the primary factor, followed by age and education. Health was not related to sexual functioning in women, and postmenopausal status was identified as a small contributor to lower levels of sexual interest and frequency but not to enjoyment.⁽³⁾

A number of changes that occur with aging have effects on sexual response (see Table 3). Despite these changes, most current studies do not show an appreciable rise in sexual problems as women age.^(1,2,5,11) For instance, baseline data from the Study of Women's Health Across the Nation (SWAN) suggest that sexual function and practices remain unchanged for premenopausal and perimenopausal women.⁽⁶⁾ The study investigated the sexual behavior of 3,262 women without hysterectomy aged 42 to 52 who were not using hormones. Although early perimenopausal women reported more frequent dyspareunia than did premenopausal women, there were no differences between the two groups in regard to sexual desire, satisfaction, arousal, physical pleasure, or the importance of sex. Seventy-nine percent had engaged in sex with a partner within the past 6 months. Seventy-seven percent of the women said that sex was moderately to extremely important to them, although 42 percent reported a desire for sex infrequently (0-2 times per month), prompting the authors to note that a "lack of frequent desire does not appear to preclude emotional satisfaction and physical pleasure with relationships."

TABLE 3. Effects of Aging on Female Sexual Function^(3,12,13)

• Decreased muscle tension may increase time from arousal to orgasm, lessen intensity of orgasm, and lead to a more rapid resolution
• Distention of the urinary meatus
• Lack of breast-size increase with stimulation
• Clitoral shrinkage, decrease in perfusion, diminished engorgement, and delay in clitoral reaction time
• Decreased vascularization and delayed or absent vaginal lubrication
• Decreased vaginal elasticity
• Decreased congestion in outer third of vagina
• Fewer, occasionally painful, uterine contractions with orgasm
• Genital atrophy
• Thinning of vaginal mucosa
• Increase in vaginal pH
• Decreased sex drive, erotic response, tactile sensation, capacity for orgasm

John Bancroft, lead author of the 1999-2000 national survey of 987 women that found emotional well-being and the quality of a relationship with a partner had more of an effect on sexuality than aging, suggests that aging affects genital response more in men than women, and sexual interest more in women than men.⁽¹⁾German researcher Uwe Hartmann, PhD, and colleagues support this view but note that: "there is a greater variability of virtually all sexual parameters with higher age, indicating that the sexuality of midlife and older women, in comparison with that of younger women, is more dependent on basic conditions like general well-being, physical and mental health, quality of relationship, or life situation. It is these factors that determine whether the individual woman can retain her sexual interest and pleasure in sexual activity."⁽⁵⁾

Many researchers suggest that the quality and quantity of sexual activity with aging are also dependent on the quality and quantity of sexual activity during earlier years.^(2,5)

Effects of Perimenopause/Menopause on Female Sexual Response

Although menopause symptoms can indirectly affect sexual responsitivity (see Table 4), as with aging, menopause does not represent an end of sex.⁽⁵⁾ Declining estrogen and testosterone levels may be associated with a flagging sex drive, but in light of Basson's recent model of the sexual response pattern, this may not be as important an occurrence as once thought.⁽¹⁴⁾ If desire is not the motivating force for sexual activity for many women, as Basson contends, then the loss of spontaneous desire may not have very much impact on a woman's sexual life at all if her partner is still interested in engaging in sex.^(2,3)

TABLE 4.Possible Changes in Sexual Function at Menopause

• Decline in desire
• Diminished sexual response
• Vaginal dryness and dyspareunia
• Decreased sexual activity
• Dysfunctional male partner

Recent studies suggest that the hormonal changes that occur during menopause have less of an effect on a woman's sexual life and response than do her feelings about her partner, whether her partner has sexual problems, and her overall feelings of well-being.^(4,5)

For instance, analysis of data from 200 premenopausal, perimenopausal, and postmenopausal women with an average age of 54 from the Massachusetts Women's Health Study II (MWHS II) showed that menopause status had less of an impact on sexual functioning than health, marital status, mental health, or smoking.⁽⁴⁾ Satisfaction with their sex life, frequency of sexual intercourse, and pain during intercourse didn't vary by women's menopausal status. Postmenopausal women did self-report significantly less sexual desire than premenopausal women (p<0.05) and were more likely to agree that interest in sexual activity declines with age. Perimenopausal and postmenopausal women also reported feeling less aroused compared with when they were in their 40s than premenopausal women (p<0.05). Interestingly, the presence of vasomotor symptoms was not related to any aspect of sexual functioning.

Declining Estrogen Levels

The loss of ovarian production of estradiol at menopause can result in vaginal dryness and urogenital atrophy, which can affect sexuality.⁽¹⁵⁾ In the MWHS II, vaginal dryness was associated with dyspareunia or pain after intercourse (OR=3.86) and difficulty experiencing orgasm (OR=2.51).⁽⁴⁾ On the other hand, a study by Van Lunsen and Laan found that sexual symptoms after menopause might be related more to psychosocial issues than to age- and menopause-induced changes in the genitals.⁽¹⁶⁾ These authors suggest that some postmenopausal women who complain of vaginal dryness and dyspareunia may be having sexual intercourse while unaroused, perhaps a longstanding practice (linked to their unawareness of genital vasocongestion and lubrication) before menopause. They may not have noticed the dryness and pain because their estrogen production was high enough that it masked a lack of lubrication.

Moodiness or depression associated with the hormonal changes of menopause also can lead to loss of interest in sex, and changes in body configuration can be inhibiting.⁽¹⁵⁾

Declining Testosterone Levels

By age 50, testosterone levels are reduced by half in women compared with age 20.^(16,17) As women enter menopause, the levels remain stable or may even increase slightly.⁽¹⁸⁾ In women undergoing removal of the ovaries (oophorectomy), testosterone levels also drop by 50 percent.⁽¹⁸⁾

Effects of Disease on Female Sexual Response

Although psychosocial factors are the focus of much discussion today in the pathogenesis of sexual disorders, physical factors remain important and cannot be dismissed (see Table 5). A variety of medical conditions can directly or indirectly affect female sexual functioning and satisfaction. For instance, through lack of adequate blood flow, a vascular disease such as hypertension or diabetes might inhibit the ability to become aroused.⁽²¹⁾ Depression, anxiety, and conditions such as cancer, lung disease, and arthritis that cause a lack of physical strength, agility, energy, or chronic pain also can affect sexual functioning and interest.^(3,14)

TABLE 5. Medical Conditions That Can Affect Female Sexuality^(21,26)

Neurologic Disorders

• Head injury
• Multiple sclerosis
• Psychomotor epilepsy
• Spinal cord injury
• Stroke

Vascular Disorders

• Hypertension and other cardiovascular diseases
• Leukemia
• Sickle-cell disease

Endocrine Disorders

• Diabetes
• Hepatitis
• Kidney disease

Debilitating Diseases

• Cancer
• Degenerative disease
• Lung disease

Psychiatric Disorders

• Anxiety
• Depression

Voiding Disorders

• Overactive bladder
• Stress urinary incontinence

In the MWHS II, depression was negatively associated with sexual satisfaction and frequency, and psychological symptoms were related to lower libido.⁽⁴⁾ Hartmann et al. also showed that women who suffer from depression are more likely to indicate low sexual desire than those without depression. ⁽⁵⁾

Procedures such as hysterectomy and mastectomy also may have a physical, as well as an emotional, impact on sexuality. Removing or altering female reproductive organs may lead to discomfort during sexual encounters (e.g., dyspareunia) and leave women feeling less feminine, sexual, and desirable.⁽²²⁾ In recent years, however, studies have suggested that elective hysterectomy may actually result in an improvement in rather than a deterioration of sexual functioning.^(23,24) Oophorectomy, on the other hand, leads to a deterioration of functioning, at least initially, because of the sudden cessation of sex hormone production and the onset of premature menopause.⁽²⁵⁾

Effects of Medications on Female Sexual Responsee

A wide array of pharmaceutical agents may cause sexual difficulties (see Table 6). Perhaps the most commonly acknowledged medications are the selective serotonin reuptake inhibitors (SSRIs) prescribed to treat depression and anxiety disorders, which can diminish sex drive and cause difficulty in experiencing orgasm.^(26,27) Antihypertensive agents are also notorious for causing sexual problems, and antihistamines may reduce vaginal lubrication.^(26,27)

TABLE 6. Medications That Can Cause Female Sexual Problems⁽²⁸⁾

Medications that cause disorders of desire

Psychoactive Medications

• Antipsychotics
• Barbiturates
• Benzodiazepines
• Lithium
• Selective serotonin reuptake inhibitors
• Tricyclic antidepressants

Cardiovascular and Antihypertensive Medications

• Antilipid medications
• Beta blockers
• Clonidine
• Digoxin
• Spironolactone

Hormonal Preparations

• Danazol
• GnRh agonists
• Oral contraceptives

Other

• Histamine H2-receptor blockers and
• pro-motility agents
• Indomethacin
• Ketoconazole
• Phenytoin sodium

Medications that cause disorders of arousal

• Anticholinergics
• Antihistamines
• Antihypertensives
• Psychoactive medications
  • Benzodiazepines
  • Monoamine oxidase inhibitors
  • Selective serotonin reuptake inhibitors
  • Tricyclic antidepressants

Medications that cause orgasmic disorders

• Amphetamines and related anorexic drugs
• Antipsychotics
• Benzodiazepines
• Methyldopa
• Narcotics
• Selective serotonin reuptake inhibitors
• Trazodone
• Tricyclic antidepressants*

*Also associated with painful orgasm..

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