The distribution of events in the human menstrual cycle

Increasing women's sexual desire: The comparative effectiveness of estrogens and androgens

Both estradiol and testosterone have been implicated as the steroid critical for modulating women's sexual desire. By contrast, in all other female mammals only estradiol has been shown to be critical for female sexual motivation and behavior. Pharmaceutical companies have invested heavily in the development of androgen therapies for female sexual desire disorders, but today there are still no FDA approved androgen therapies for women. Nonetheless, testosterone is currently, and frequently, prescribed off-label for the treatment of low sexual desire in women, and the idea of testosterone as a possible cure-all for female sexual dysfunction remains popular. This paper places the ongoing debate concerning the hormonal modulation of women's sexual desire within a historical context, and reviews controlled trials of estrogen and/or androgen therapies for low sexual desire in postmenopausal women. These studies demonstrate that estrogen-only therapies that produce periovulatory levels of circulating estradiol increase sexual desire in postmenopausal women. Testosterone at supraphysiological, but not at physiological, levels enhances the effectiveness of low-dose estrogen therapies at increasing women's sexual desire; however, the mechanism by which supraphysiological testosterone increases women's sexual desire in combination with an estrogen remains unknown. Because effective therapies require supraphysiological amounts of testosterone, it remains unclear whether endogenous testosterone contributes to the modulation of women's sexual desire. The likelihood that an androgen-only clinical treatment will meaningfully increase women's sexual desire is minimal, and the focus of pharmaceutical companies on the development of androgen therapies for the treatment of female sexual desire disorders is likely misplaced.

Implication of a Time-Dependent Model of Sexual Intercourse within the Menstrual Cycle

A time-dependent model of the probability of sexual intercourse, where the probability increases as the time from last intercourse increases, can produce waves in the expected frequency of sexual intercourse on the various dates of the menstrual cycle. These waves occur when the time-dependent model is linked with a period of abstinence, such as is usually found in most societies during the time of the menses. Previously, such waves have been attributed to cyclic hormonal changes in women without considering the full implication of a time-dependent model of sexual intercourse.

Auditory brain stem response throughout the menstrual cycle

A prospective study was performed to evaluate the changes in the auditory brain stem response (ABR) that occur in healthy premenopausal women throughout the menstrual cycle. Ninety-four women with ovulatory menstrual cycles underwent ABR testing by auditory evoked potentials for wave I, III, and V latencies and for interpeak I-III, I-V, and III-V intervals during the follicular, periovular, and luteal phases of the menstrual cycle. The wave latencies and the interpeak intervals showed shorter values during the periovular phase than during the luteal phase (p < .05) and shorter values during the follicular phase for wave I (p < .05) and interpeak interval I-V (p < .05). The ABR seems to be influenced by the variations of ovarian steroids that occur during the menstrual cycle.

Sexual behavior in lesbian and heterosexual women: relations with menstrual cycle phase and partner availability

Using a prospective design over three complete menstrual cycles, 147 heterosexual and 89 lesbian women made daily recordings of their basal body temperature (BBT), cervical mucus status, menses, and completed a daily checklist of various sexual behaviors (including sexual self-stimulation and sexual activity with a partner). They also gave their age, height, weight, age at menarche, number of pregnancies, duration of sleep, tobacco, caffeine, and alcohol use, and whether they had a live-in sexual partner. Using BBT, cervical mucus status, and menses information, cycle days were grouped into five discrete phases: menses, follicular, ovulatory, early luteal, and premenstrual. Daily frequencies of sexual behavior with a partner and autosexual behavior were computed for each phase. Mixed ANOVAs on the resultant proportional data revealed similar patterns for autosexual behavior across the phases for both heterosexuals and lesbians who did not have a live-in partner, in which autosexual behavior was highest during the follicular and ovulatory phases. For those with live-in partners, autosexual behavior did not vary across the phases. Lesbians engaged in more autosexual behavior overall. Allosexual behavior peaked during the follicular phase for both heterosexuals and lesbians, and the phasic pattern was unrelated to live-in partner status. Additional analyses suggest that the observed patterns were unrelated to anticipated changes in sexual activity due to menses. Results are discussed in terms of social variables and hormonal fluctuations associated with the menstrual cycle.

The nature of human orgasm: a critical review of major trends

This critical review presents a synthesis of the available theoretical and empirical literatures on human orgasm. Findings from both normal and clinical human populations are included. Two major trends in the literature, the dichotomization of biological and psychological perspectives and the assumption of gender differences, are highlighted. A new multidimensional model of the psychological experience of orgasm is described with a view to futhering a biopsychological approach applicable to both sexes. Clinical applications of this new model are discussed.

Menstrual cycle variation of women's interest in erotica

Female respondents were given the opportunity to choose feature films for viewing. Choices were made on the basis of synopses and promotional videos. These materials projected (i) a focus on erotic, sexual events, (ii) romantic themes, (iii) action-packed violent drama, and (iv) hilarious comedy. Additionally, respondents evaluated the appeal of the projected films. Respondents' position in the menstrual cycle was then determined, with placement into one of seven 4-day phases. Measured in both choices and evaluations, a postmenstrual surge in erotic interest was evident. Erotic interest was also pronounced prior to and during menses. In contrast, it was at a minimum during the first half of the luteal phase. The choice of romantic films was not appreciably influenced by cycle position. However, in evaluating films with romantic themes, premenstrual women expressed particularly little interest in this genre.

Salivary testosterone measurements: reliability across hours, days, and weeks

Salivary testosterone measurements would appear to be useful in behavioral research, where subjects are often reluctant to provide serum samples. The usefulness of salivary measurements depends upon their reliability, however, which was the focus of the present investigation. In four studies, 270 male and 175 female subjects collected saliva samples at times ranging from 30 min to 8 weeks apart. Subjects collected samples on at least two days, at time of awakening, midmorning, late afternoon, and late evening. Mean testosterone concentration dropped about 50% from morning to evening for both sexes, with largest drops early in the day. Mean reliability was r = .64 across two days and r = .52 across seven-eight weeks. Menstrual cycle effects were negligible. Reliability can be increased by using more than one measurement, and it is probably desirable to combine measurements taken several weeks apart. Salivary assays offer a practical way of measuring testosterone in free-ranging subjects outside the laboratory.

Low sexual desire in women: the role of reproductive hormones

The role of reproductive hormones in mediating sexual desire in healthy women is still unclear. Elucidation was sought in this study by comparing the hormonal milieu of two groups of subjects with markedly different levels of sexual desire. Seventeen women ages 27-39 who met DSM III-R criteria for severe, persistent, and generalized loss of desire (hypoactive sexual desire disorder, HSD), but had no other current psychological or medical problem, were compared to 13 healthy, sexually active women. All subjects and spouses were interviewed extensively to determine the women's sexual desire and responsiveness. Blood samples were drawn every 3 to 4 days for one menstrual cycle and were analyzed by RIA for testosterone, SHBG, estradiol, progesterone, prolactin, and luteinizing hormone. Results indicated that the HSD women's gonadal hormones fluctuated normally over the menstrual cycle, were within normal limits for each cycle phase, and were never significantly different from those of controls. Neither testosterone, non-SHBG bound testosterone, nor prolactin differentiated between the HSD women with the most and least severe HSD parameters (e.g., frequency of fantasy, masturbation, or female-initiated coitus), nor between women with lifelong and acquired HSD. The present findings did not provide evidence that reproductive hormones are important determinants of individual differences in the sexual desire of these eugonadal women.

Mood and the menstrual cycle

A majority of women are aware of menstrual cycle-related changes in mood and behaviour. Psychiatric disorders may also be influenced by the menstrual cycle. A premenstrual tension syndrome has been described. Research into the prevalence, aetiology and management of this condition has been hampered by additions and alterations to the original description and methodological difficulties involved in menstrual cycle research. Biological, psychological and sociological theories have been proposed to explain menstrual cycle-related mood changes. Our own studies have found evidence of ovarian steroid disturbances, and impaired psychological functioning in women with the premenstrual syndrome. Therapeutic approaches must consider both aspects. Medication often makes the patient more accessible and receptive to regimens aimed at increasing coping skills. More vigorous research into this disorder is needed.

The influence of age and cycling status on sexual arousability in women

The effects of age and hormonal status on sexual response were quantitatively assessed by the use of a vaginal photoplethysmograph to measure changes in pulse amplitude in response to erotic film and fantasy. In young, regularly cycling women (mean age, 31 years) there were no significant differences in sexual response between the follicular, ovulatory, and luteal phases. The older premenopausal women (mean age, 51 years) showed responses not significantly different from those of the young cycling women. However, both the younger cycling women and older premenopausal women had significantly higher responses to erotic film than the postmenopausal women (mean age, 57 years). It was concluded that the menopause does result in a decrease in sexual response as assessed by vaginal pulse amplitude. However, it was not established that the magnitude of change noted is sufficient to cause any sexual dysfunction.

Affect and the menstrual cycle

Evidence from both retrospective and prospective studies suggests that many women do show cyclical changes in affect. Negative changes such as irritability, headache, tension, anxiety, sleep disturbance and depression are more frequent in the premenstrual and menstrual phases. Positive changes, pleasantness, increased vigour and elation are reported more often in the follicular or mid-cycle phases. Various theories have been suggested to explain these changes. These include psychodynamic, sociological and biological explanations. Although there is some evidence to support each theory no definite conclusions can be reached about the aetiological basis of most affective changes. Interpretation of studies attempting to link hormonal and affective fluctuations in limited by the many methodological problems outlined. Only one study appeared able to conclusively demonstrate a hormonal basis for a cyclical symptom. Suggestions are made for further research in this area.