This large, community-based study of middle-aged women found a decrease in sexual desire, increase in painful intercourse beginning in the late perimenopause, and a temporary increase in masturbation during early perimenopause. These changes were independent of chronological aging, menopausal symptoms, and health, social, and psychological factors. In adjusted analyses, menopausal transition was unrelated to arousal, frequency of sexual activity, physical pleasure, or satisfaction with partner. Although vasomotor symptoms were largely unrelated to sexual functioning, vaginal dryness was highly associated with pain and lower arousal, emotional satisfaction, and physical pleasure. The most important variable related to sexual functioning was importance of sex, which was highly related to all outcomes. Psychological status, physical health, and relationship status were also important.
We did not find that hormone therapy users reported better sexual functioning, but these results must be interpreted with caution. Current and former hormone therapy users reported more physical pleasure, but also more vaginal/pelvic pain. However, the timing of hormone therapy in relation to the experience of pain and desire was not assessed and we could not determine whether hormone therapy provided any diminution of pain or increase in desire. The reason for hormone therapy use was not available and menopausal status was not determinable for women who initiated hormone therapy prior to the final menstrual period. The consistent pattern of results for both current and former users suggest “confounding by indication.” That is, women who have a troublesome symptom (such as vaginal/pelvic pain) chose to take estrogen to treat the problem, making it appear that pain is an effect of hormone therapy. We should note, however, that the present study was not designed to determine the effect of hormone therapy on sexual functioning, a question best addressed in a clinical trial in which treatment assignment is random.
Findings of an association between menopause transition and an increase in vaginal or pelvic pain and a decrease in sexual desire, independent of aging and a range of covariates, strengthens results from cross-sectional studies that have shown greater pain16, 35, 36
and lower sexual interest or desire among peri or postmenopausal women.9,11,12,20,35
The increase in masturbation during early perimenopause is an interesting finding and may be related to the concurrent increase in painful intercourse. The decline in masturbation post menopause may be related to the concurrent decline in desire. The lack of an association between menopause transition and frequency of sexual intercourse or satisfaction with partner is also consistent with other cross-sectional research12,19,20
and, together with the lack of an association with importance of sex and arousal, suggests that these domains of sexual function are not directly related to the menopause transition.
These results suggest a plausible causal pattern underlying declines in sexual functioning as increases in pain may lead to lowered sexual desire. Vulvovaginal epithelium is rich in estrogen receptors, and estrogens are a necessity for urogenital maturation, maintenance and genital vascular congestion during arousal.37
Lower estrogen levels in the late transition may lead to decreased vascular engorgement and vaginal secretions during sex, resulting in a diminished sense of pleasure from subjective arousal and a disruption in the intimacy-based sexual response cycle.38
These results from SWAN highlight the importance of including social, health, and relationship factors in the context of menopause and sexual functioning. These factors and in particular, feelings toward one’s partner or starting a new relationship, have also been identified by others as highly important.1,10,19,20,39–42
Similar to the Melbourne Women’s Midlife Health Project (MWMHP), we found declines in all areas of sexual functioning in unadjusted analyses of menopausal status. Controlling only for age, the MWMHP also found greater declines in sexual functioning among 197 women who transitioned from pre to postmenopause compared to women who remained premenopausal.4
Subsequent analyses from the Melbourne study found that prior sexual function and relationship factors were more important determinants of libido and sexual responsiveness than estradiol level.6
Although the Penn Ovarian Aging Study found an increase in overall sexual dysfunction with advanced menopausal status, several critical factors such as health, vaginal dryness, aging, and relationship status were not assessed.10
Despite controlling for a wide range of variables, we found racial/ethnic differences for all outcomes. African-American women reported higher frequency of sexual intercourse, consistent with other research showing that African-American women are more likely to engage in vaginal intercourse than other sexual activities such as oral or anal intercourse.2,26,43,44
Findings for Chinese and Japanese women are consistent with data showing that Asian women tend to engage in fewer different manifestations of sexuality than Western women and that sexuality is more linked to procreation in Asian cultures.45
Results are also consistent with findings from the Global Study of Sexual Attitudes and Behaviors which found that Asian countries reported low levels of satisfaction with sexual function and the importance of sex.46
These findings suggest that sexual behavior has a strong cultural component.
Several limitations of these data should be mentioned. First, the questionnaire did not include items on the sexual limitations of the woman’s partner, an important consideration for aging women. Second, the sexual functioning questionnaire was not one of the more newly developed, validated questionnaires.35,47
However, the items were derived from previously published questionnaires and tap the primary domains of sexual functioning assessed by these measures. Third, as is inevitable in longitudinal studies, some participants missed visits or were lost to follow-up, resulting in missing data. The analytic methods used are relatively robust to missing data, and multivariable models incorporated numerous factors strongly associated with the likelihood of data being missing. However, the potential impact of missing data on analysis results should be considered. Future research in this area needs to examine partner limitations more closely and follow women through the early postmenopausal years. This analysis did not consider the possible relation between sexuality and sex steroid levels – a complex question that demands a detailed analysis and will be the subject of future SWAN work.
These results from SWAN have clinical relevance. Therapy to prevent menopause transition-associated vaginal pain may help slow or prevent subsequent/simultaneous declines in sexual desire. The strong associations of psychological status, physical health, and social factors with sexual function underscore the clinical imperative to explore and address these factors when discussing women’s concerns regarding sexual dysfunction. The very strong association of the importance of sex with all domains of sexual function suggests that asking patients about the importance of sex may be a cornerstone of the management of the sexual concerns of midlife women.