Women's sexual experience during the menstrual cycle: identification of the sexual phase by noninvasive measurement of luteinizing hormone

Journal of Sex Research, Feb, 2004 by Susan B. Bullivant, Sarah A. Sellergren, Kathleen Stern, Natasha A. Spencer, Suma Jacob, Julie A. Mennella, Martha K. McClintock

Methods

Measures and procedure. Forty-six women each contributed data from one menstrual cycle. Menstrual cycle phases were determined as described above in the section "A Noninvasive Method for Precisely Identifying Phases of the Menstrual Cycle." In addition to providing daily menstrual cycle and sexual activity data, participants also answered daily log book questions to quantify the following as continuous psychosocial variables: strength of sexual desire, number of sexual fantasies, and intensity of loneliness. These logbook entries were completed each evening and contained a multitude of items concerning physical activity, symptoms, illnesses, and psychosocial variables. No subject detected our focus on sexuality.

Sexual activity. Sexual activity was defined during the training session as any sexual activity either with a partner or alone, and thus included autoerotic and other sexual activities in addition to sexual intercourse. Participants were also asked to indicate whether the sexual activity was initiated by oneself, one's partner, or equally by both, and to indicate what if any birth control methods were used.

Sexual desire. To assess strength of desire for sexual intimacy, participants were asked to indicate on a visual analog scale "the degree (frequency, intensity or duration) to which you felt desire today for sexual intimacy with other people (e.g. your partner, friends, strangers, etc.)". The poles were labeled not at all and very much. The strength of desire was quantified by measuring to the nearest millimeter the length of the line and the point on that line marked by the participant, and calculating the proportion to create a scale between 0 and 1.0.

Sexual fantasies. The sexual fantasy variable was assessed using a yes/no question in which participants were asked whether they recalled "having any fantasies/daydreams today which were of a sexual or romantic nature" and, if so, to estimate the number. If a participant gave a range for the number of fantasies (e.g., 4-6) the mean was used. We found large individual differences in numbers of fantasies reported, which were potentially greater than the effect of menstrual cycle hormones. To standardize for these individual differences, we based data on a z score calculated for each woman's daily average.

Loneliness. We assessed psychosocial loneliness with a single item in the logbook, which asked participants to check a box if they had felt lonely that day.

Partnership status. Whether a woman was considered to have a sexual partner during the cycle was determined using two sets of criteria. Women considered "partnered" for a cycle either (a) slept in the same bed as another person identified as "boyfriend, girlfriend or husband" at least 15% of the nights of the cycle, and review of sexual activity data indicated an increase of activity on those days; or (b) did not meet criteria a but review of sexual activity data and retrospective self-reported partnership status clearly indicated that they had a regular sexual partner during that cycle.