Social jetlag and menstrual symptoms among female university students

Menstrual symptoms may have a significant impact on women’s lives. Many women experience menses-related health problems, such as menstrual pain, heavy menstrual bleeding, and premenstrual syndrome, during their reproductively fertile years. Circadian misalignment in shift workers has been reported to contribute to menstrual cycle irregularity and/or painful menstruation. However, the relationship between social jetlag (SJL) and menstrual symptoms/menstrual cycle has not been elucidated. In this study, we aimed to elucidate this relationship among female university students. One-hundred and fifty female university students (mean [SD]: 18.8 [0.71]-years old) completed self-reported questionnaires consisting of menstrual symptoms and menstrual cycle, sleep quality and sleep habits, quality of life, and demographic variables. The average menstrual cycle was 32.0 [5.4] days. The percentage of students who showed menstrual cycle irregularity, having less than 25 days or more than 39 days of menstrual cycle during the previous four menstrual cycles, was 60.6%. SJL, the difference between mid-sleep time on free days and mid-sleep time on school days, was categorized into small (absolute SJL < 1 h) or large (≥1 h). Overall, 78.0% of participants had SJL ≥ 1 h. Among the menstrual symptoms, pain, behavioral change, and water retention subscale scores were significantly higher in the SJL ≥ 1 h group than in the SJL < 1 h group. However, no significant differences were found in concentration, autonomic reaction, or negative affect subscale scores between the two groups. The menstrual cycle was 31.2 [5.5] days in the SJL < 1 h group and 32.2 [5.4] days in the SJL ≥ 1 h group, without significant difference. Logistic regression analysis showed that more than 1 h of SJL was a significant associated factor with severe menstrual symptom, independently of sleep duration and late chronotype. This study indicated that SJL was a significant factor associated with severe menstrual symptoms, suggesting the possibilities of association between circadian system and reproductive function among humans.     

Effect of oral contraceptives and some psychological factors on the menstrual experience

This study attempts to clarify the etiology of menstrual distress by using objective measures of menstration, enlightened statistical treatment and standardized measures of psychological factors. In addition to observing the traditionally associated psychological factors, measures of health locus of control, preventive health behavior and menstrual socialization (e,g., age at menarche) are included in order to assess the relevance of attitudes towards health. 57 women (mean age=23.5 years), 1/2 of whom (29) used an oral contraceptive, completed Moos' menstrual distress questionnaire at each of the 3 menstrual phases. In addition they kept menstrual diary cards for 50 days, recording days on which menstrual blood loss occurred. During an intermenstrual phase, they completed a general information questionnaire with questions on menstrual socialization and demographic variables; Eysenck's personality inventory; the multidimensional health locus of control scale; the Bem sex role inventory; and a measure of preventive health behavior. Analyses investigating the effects of pill use and psychological factors on the incidence and intensity of menstrual distress found few significant associations between these measures, especially when symptom changes over the menstrual cycle were the dependent variables. The results generally support the notion that menstruation is a negative event for most women (2/3 of the sample). Neuroticism was found to correlate with all the premenstrual MDQ scores except the positive aspect of increased arousal, with negative affect at both menstrual and intermenstrual phases, with menstrual pain and with intermenstrual concentration. The regression analyses indicate that changes in symptoms of menstrual distress over the menstrual cycle are not well predicted by the measures investigated in this study. Of the few significant associations noted, most are explicable in common sense terms. The more objective approach adopted in this study gives little support for a psychological etiology of distres. However, it also queries the appropriateness of a physiological explanation because of the limited differences found between pill users and nonusers. The inability of locus of control scores, menstrual socialization measures and a preventive health behavior measure to contribute to the definition of a woman at risk, suggests that distress is not related to an individual's general health concepts nor perceived control. 1 aspect not investigated in this study and a topic for future research is the role of a woman's expectations on her experience.     

Oral contraceptive use and increased plasma concentration of C-reactive protein

We examined, in young adult women, the association between current low dose oral contraceptive (OC) use and plasma levels of C-reactive protein (CRP), an acute phase reactant predictive of cardiovascular disease risk. We conducted a cross-sectional analysis of 30 healthy, non-smoking, non-obese women (18 OC users and 12 nonusers) who were subjects in a randomized diet-controlled trial of the effects of soy intake on sex hormone metabolism. The study was sited at a university outpatient general clinical research center. Fasting plasma CRP levels were measured 4 times during 2 menstrual cycles (2 mid-follicular phase and 2 mid-luteal phase) using a high-sensitivity CRP assay. Differences between OC users and nonusers were examined by 3-way analysis of variance. Multiple regression was used to examine the relationship between OC use and CRP. There were no significant differences in baseline demographic characteristics between OC users and nonusers. Plasma CRP levels (mean +/- SE) were 2 times higher among OC users than among non-users (2.0 +/- 0.2 versus 0.9 +/- 0.3 mg/l, p<0.0001) independent of diet assignment, diet treatment order, and phase of the menstrual cycle. In a multivariate model, OC use predicted 32 percent of the variance in CRP levels (p<0.0001). As all CRP levels were within a previously established normal range, further study is indicated to establish the clinical significance of the observed elevated CRP levels in OC users.     

Effects of 12-hour rotating shifts on menstrual cycles of photoelectronic workers in Taiwan

12 h rotating shifts are common in high-tech industries in Taiwan. The aim of this longitudinal study was to evaluate the effect of the disruption of circadian rhythms by the shift schedule on menstrual cycle length (MCL) and regularity of female workers at an optoelectronic company in Taiwan. We recruited females who worked rotating shifts in a clean room environment as the shift-work group and female office workers who worked normal business hours as the comparison group. Every participant recorded their MCL for each menstruation cycle up to eight consecutive months prospectively and provided demographic characteristics, reproductive history, and menstrual characteristics. We collected data on 1,135 and 117 menstruation cycles in the shift-work (n = 280) and comparison groups (n = 49). Whereas the two groups had similar group means for MCL and number of menstrual bleeding days, the prevalence of menstrual cycle irregularity (cycles <25 or >35 days) was higher in the shift-work group ( p = 0.04). Univariate and multivariate logistic regression analyses demonstrated that rotating shift work was an independent predictor of menstrual cycle irregularity (odds ratio = 1.71, 95% confidence interval: 1.03-2.88) after adjusting for shift-work history, employment duration, coffee consumption,and pre-employment menstrual cycle irregularity. Although further study is required to confirm our findings plus to explore prevention and control measures, our data indicate rotating shift work can increase the risk of MCL irregularity.     

Methods for quantitative and qualitative evaluation of vaginal microflora during menstruation

The quantitative and qualitative changes in the bacterial flora of the vagina during menstruation have received inadequate study. Similarly, the effect of vaginal tampons on the microbial flora as well as the relationship between the microbial flora of the vagina and that of the tampon has not been adequately evaluated. The purposes of the present study were (i) to develop quantitative methods for studying the vaginal flora and the flora of tampons obtained during menstruation and (ii) to determine whether there were differences between the microflora of the tampon and that of the vaginal vault. Tampon and swab samples were obtained at various times from eight young healthy volunteers for 8 to 10 menstrual cycles. Samples consisted of swabs from women wearing menstrual pads compared with swab and tampon samples taken at various times during the menstrual cycle. Samples were analyzed for total facultative and anaerobic bacterial counts, and the six dominant bacterial species in each culture were identified. Statistical evaluation of the results indicates that total bacterial counts decreased during menstruation and that swab and tampon samples yielded similar total counts per unit weight of sample. The numbers of bacteria in tampons tended to be lower than in swabs taken at the same time. Overall, during menstruation, the concentrations of lactobacilli declined, but otherwise there was little difference among the species found during menstruation compared with those found in intermenstrual samples. Cotton tampons had little discernible effect on the microbial flora.     

Methods for quantitative and qualitative evaluation of vaginal microflora during menstruation.

The quantitative and qualitative changes in the bacterial flora of the vagina during menstruation have received inadequate study. Similarly, the effect of vaginal tampons on the microbial flora as well as the relationship between the microbial flora of the vagina and that of the tampon has not been adequately evaluated. The purposes of the present study were (i) to develop quantitative methods for studying the vaginal flora and the flora of tampons obtained during menstruation and (ii) to determine whether there were differences between the microflora of the tampon and that of the vaginal vault. Tampon and swab samples were obtained at various times from eight young healthy volunteers for 8 to 10 menstrual cycles. Samples consisted of swabs from women wearing menstrual pads compared with swab and tampon samples taken at various times during the menstrual cycle. Samples were analyzed for total facultative and anaerobic bacterial counts, and the six dominant bacterial species in each culture were identified. Statistical evaluation of the results indicates that total bacterial counts decreased during menstruation and that swab and tampon samples yielded similar total counts per unit weight of sample. The numbers of bacteria in tampons tended to be lower than in swabs taken at the same time. Overall, during menstruation, the concentrations of lactobacilli declined, but otherwise there was little difference among the species found during menstruation compared with those found in intermenstrual samples. Cotton tampons had little discernible effect on the microbial flora.     

Effects of 12‐Hour Rotating Shifts on Menstrual Cycles of Photoelectronic Workers in Taiwan

12 h rotating shifts are common in high‐tech industries in Taiwan. The aim of this longitudinal study was to evaluate the effect of the disruption of circadian rhythms by the shift schedule on menstrual cycle length (MCL) and regularity of female workers at an optoelectronic company in Taiwan. We recruited females who worked rotating shifts in a clean room environment as the shift‐work group and female office workers who worked normal business hours as the comparison group. Every participant recorded their MCL for each menstruation cycle up to eight consecutive months prospectively and provided demographic characteristics, reproductive history, and menstrual characteristics. We collected data on 1,135 and 117 menstruation cycles in the shift‐work (n=280) and comparison groups (n=49). Whereas the two groups had similar group means for MCL and number of menstrual bleeding days, the prevalence of menstrual cycle irregularity (cycles<25 or>35 days) was higher in the shift‐work group (p=0.04). Univariate and multivariate logistic regression analyses demonstrated that rotating shift work was an independent predictor of menstrual cycle irregularity (odds ratio=1.71, 95% confidence interval: 1.03–2.88) after adjusting for shift‐work history, employment duration, coffee consumption, and pre‐employment menstrual cycle irregularity. Although further study is required to confirm our findings plus to explore prevention and control measures, our data indicate rotating shift work can increase the risk of MCL irregularity.     

Genetic and environmental determinants of menstrual characteristics

BACKGROUND:

The impact of women''s menstrual cycle on her quality of life, health, work, and community is substantial. Menstrual disturbance is linked with general ill conditions such as migraine, asthma, and endocrinopathies. The clinical significance of medical interventions to prevent these conditions becomes clear if the role of genetic or environment is clarified.

AIMS:

To identify the genetic and environmental contribution on menstrual characteristics.

SETTING AND DESIGN:

This was a cross-sectional study in 2 Asian countries.

MATERIALS AND METHODS:

2 cohorts of monozygotic and dizygotic twins born between (1945-1988, n = 122) and (1951-1993, n = 71) were taken. A standard questionnaire was designed inclusive of socio- demographic characteristics of subjects as well as menstrual history (duration, interval, amount, irregularity). Subjects were interviewed by phone.

STATISTICAL ANALYSIS:

Quantitative variables were analyzed using Falconars’ formula as well as maximum likelihood analysis. Structural modeling was then applied to twin correlations to provide estimates of the relative genetic and/or environmental factors contribution in determining the measured trait.

RESULTS:

Menstrual characteristics were found to be under environmental influence where the best fitting model for menstrual interval and duration was common environment. CDF plotting confirmed the results for both variables. Proband-wise concordance analysis for amount of menstruation, amenorrhea, and irregular menstruation revealed no genetic influence. The best fitting model for menstrual irregularity was CE (C73%, E27%). The same model was defined for amenorrhea (C48%, E52%).

CONCLUSIONS:

Environmental factors are most likely responsible to determine the menstrual flow, its integrity, and regularity. These factors need to be studied further.     

Attractiveness of women's body odors over the menstrual cycle: the role of oral contraceptives and receiver sex

It is a long held assumption that women have concealed ovulation,which means that men do not know when women's menstrual cyclesare in their most fertile phase. Recent empirical results haveprovided evidence that ovulation may not be totally concealedfrom pair-bonded males, but the generality and the mechanismsof the finding demand further study. To examine the possibleadaptive value of the phenomenon, it is necessary to study whetherthe ability to detect ovulation is confined to males. We studiedthese questions in an experiment in which male and female ratersrated the sexual attractiveness and intensity of T-shirts' odorsworn by 42 women using oral contraceptives (pill users) andby 39 women without oral contraceptives (nonusers). Males ratedthe sexual attractiveness of nonusers highest at midcycle. However,female raters showed only a nonsignificant trend for this relationship.Neither sex rated attractiveness of the odors of pill usersaccording to their menstrual cycle. The results indicate thatmen can use olfactory cues to distinguish between ovulatingand nonovulating women. Furthermore, the contrasting resultsbetween pill users and nonusers may indicate that oral contraceptivesdemolish the cyclic attractiveness of odors. Together, thesefindings give more basis for the study of the role of odorsin human sexual behavior.     

Testosterone and sexual behavior in oral contraceptive users and nonusers: a prospective study

The relationship between plasma testosterone (T) secretion and patterns of sexual behavior was examined in 18 women using oral contraceptives (OCs) and 13 nonusers matched for partner availability. Retrospective assessments of perimenstrual symptoms, sexual attitudes, and sexual experience were obtained and women completed daily ratings of the frequency of sexual activities and the level of well-being for 1 month. Plasma levels of sex hormone binding globulin (SHBG), progesterone, Total T, Free T, and non-SHBG bound T were determined by radioimmunoassay at four phases of the pill or menstrual cycle. Overall, women not using OCs had higher plasma levels of Total, Free, and non-SHBG bound T and lower plasma levels of SHBG than those of OC users. Further, only nonusers had perimenstrual decreases in plasma levels of Total and Free T. The two groups were comparable on most retrospective measures. However, OC users reported more satisfaction with their sexual partners than did nonusers and prospective monitoring revealed that they engaged in sexual interactions more frequently than did nonusers across the cycle. In contrast, both groups reported a similar frequency of autosexual activities across the cycle. There were no correlations between average levels of T and levels of sexual desire, sexual interactions, or autosexuality. Moreover, only nonusers reported a decrease in levels of sexual desire during the perimenstrual period that was associated with the changes in Free T over the menstrual cycle.     

Influence of menstrual cycle and oral contraceptives on tolerance to uncompensable heat stress

In this study we examined the influence of menstrual cycle phase and oral contraceptive use on thermoregulation and tolerance during uncompensable heat stress. Eighteen women (18-35 years), who differed only with respect to oral contraceptive use (n = 9) or non-use (n = 9), performed light intermittent exercise at 40 degrees C and 30% relative humidity while wearing nuclear, biological and chemical protective clothing. Their responses were compared during the early follicular (EF, days 2-5) and mid-luteal (ML, days 19-22) phases of the menstrual cycle. Since oral contraceptives are presumed to inhibit ovulation, a quasi-early follicular (q-EF) and quasi-mid-luteal (q-ML) phase was assumed for the users. Estradiol and progesterone measurements verified that all subjects were tested during the desired phases of the menstrual cycle. Results demonstrated that rectal temperature (Tre) was elevated in ML compared with EF among the non-users at the beginning and throughout the heat-stress trial. For the users, Tre was higher in q-ML compared with q-EF at the beginning, and for 75 min of the heat-stress exposure. Tolerance times were significantly longer during EF [128.1 (13.4) min, mean (SD)] compared with ML [107.4 (8.6) min] for the nonusers, indicating that these women are at a thermoregulatory advantage during the EF phase of their menstrual cycle. For the users, tolerance times were similar in both the q-EF [113.0 (5.8) min] and q-ML [116.8 (11.2) min] phases and did not differ from those of the non-users. It was concluded that oral contraceptive use had little or no influence on tolerance to uncompensable heat stress, whereas tolerance was increased during EF for non-users of oral contraceptives.     

The Unique Impact of Menstruation on the Female Voice: Implications for the Evolution of Menstrual Cycle Cues

Research shows that hormonal changes in women across the menstrual cycle affect vocal production. Most work has documented shifts at high fertility times (i.e., ovulation) or during premenstruation. However, hormonal changes at menstruation also affect female physiology and behavior and could affect vocal production. The present studies investigated perceptual differences in voices recorded during menstruation compared with recordings taken at other times of the menstrual cycle. Results show that male raters could reliably identify voices recorded during menstruation with or without the presence of a voice recorded closest to ovulation. In addition, voices recorded at menstruation were identified as being the most unattractive. These findings indicate that voice recordings taken at times of lowest fertility may uniquely impact women’s vocal production and that perceptions of voice based on cycle phase are not specific to the time of heightened fertility. Implications for the evolution of human menstrual cycle cues are discussed.     

Lower interleukin-2 and higher serum tumor necrosis factor-a levels are associated with perimenstrual, recurrent, facial Herpes simplex infection in young women

The aim of this study was to look at a possible relationship between the recurrent perimenstrual dermatosis - facial Herpes simplex infection and the serum concentrations of interleukin-2 (IL-2) and tumor necrosis factor alpha (TNF-alpha). Twenty-one volunteers (19-26 year olds) were examined at five points of the menstrual cycle. Ten volunteers were characterised by recurrent Herpes simplex infection lasting either from the 18th or the 25th day of the menstrual cycle until a few days after menstruation. Eleven young women without symptoms formed the control group. Both groups were similar as regards blood levels of 17beta-estradiol and progesterone. The group with the frequent infectious symptoms was characterised, however, by lower concentrations of IL-2 throughout the whole menstrual cycle, as compared to those without the symptoms. Levels of IL-2 in this group additionally dropped significantly on the 18th and on 25th day of the cycle. Moreover, the group with symptoms was characterised by higher level of TNF-alpha on the 18th day. These changes were found during the menstrual cycle of the women with recurrent herpes infection who however, at the time of the examination were free of the clinical symptoms. There was a similar tendency in both groups towards an increase in the levels of TNF-a around menstruation. Measurement of the other serum pro-inflammatory marker - IL-6 showed higher levels of this cytokine during the menstrual cycle in the group with the clinical symptoms. The results indicate that a decrease of IL-2 together with an increase of TNF-alpha and IL-6 in the serum seem to be related to recurrent perimenstrual Herpes simplex infection.     

Psychophysical characteristics of the premenstrual period

Aim of this study was to investigate psychophysical characteristics of the premenstrual period in regard to the period following menstruation. Psychophysical characteristics are defined as assessments of the physical state (fatigue, breast tenderness, bloating and lack of sleep), emotional state (happiness, anger, sadness, irritability, anxiety and distraction) and general assessments of physical attractiveness and satisfaction with oneself Diary of psychophysical characteristics was designed for this study as well as a socio-demographic questionnaire and a menstrual cycle calendar. 51 healthy, non-help-seeking women, aged 21-46 kept a diary of psychophysical characteristics a week before menstruation and four days one week after the onset of menstruation, during two menstrual cycles. The premenstrual period is characterized by the intensification of negative emotional states, the decline of positive emotional states, and the worsening of the general self-image through the decline of the perception of physical attractiveness and satisfaction with oneself In conclusion, the premenstrual period is not marked only by the mood-swings but also by the changes in the cognitive representation of self     

Poststerilization regret among women: methodological considerations for the next decade

The literature concerning regret among women following voluntary sterilization shows a lack of methodological rigor. This paper reviews the 7 prospective studies of voluntary sterilization conducted since 1973 that are judged to have adequate design and measurement standards, and suggests methodological considerations for future research. 3 of the studies were conducted in the US, 2 in the UK, 1 in Thailand, and 1 in Pakistan. Only 3 of the 7 studies used control groups and only 3 used standardized pre- and posttest psychological measures. Subjects in all the studies requested sterilization on a voluntary basis. 4 of the 7 studies evaluated contraceptive and menstrual histories before and after sterilization. All the studies varied in their poststerilization follow-up intervals ranging from 2 months and 1 year to 18 months and 2 years. Attrition rates also varied widely across the studies. Although none of these studies presented percentages for precise measures of regret, the overall effect of the sterilization procedure was found to be positive. The relationship between regret and purported indicators of regret, such as depression, anxiety, menstrual difficulties, and desire for reversal, should be documented in prospective, controlled studies. Longer poststerilization follow-up periods are recommended. Responses of childless women and male partners to sterilization should also be considered in future studies. Finally, since repeated references are made to menstrual problems following voluntary sterilization, it is important that studies assessing poststerilization responses control for oral contraceptive (OC) use because OCs reduce menstrual flow and their discontinuation results in a return to normal, although heavier, menstrual flow.     

Comprehensive analysis of leukocytes, vascularization and matrix metalloproteinases in human menstrual xenograft model

In our previous study, menstrual-like changes in mouse were provoked through the pharmacologic withdrawal of progesterone with mifepristone following induction of decidualization. However, mouse is not a natural menstruation animal, and the menstruation model using external stimuli may not truly reflect the occurrence and development of the human menstrual process. Therefore, we established a model of menstruation based on human endometrial xenotransplantation. In this model, human endometrial tissues were transplanted subcutaneously into SCID mice that were ovarectomized and supplemented with estrogen and progestogen by silastic implants with a scheme imitating the endocrinological milieu of human menstrual cycle. Morphology, hormone levels, and expression of vimentin and cytokeratin markers were evaluated to confirm the menstrual-like changes in this model. With 28 days of hormone treatment, transplanted human endometrium survived and underwent proliferation, differentiation and disintegration, similar to human endometrium in vivo. Human CD45+ cells showed a peak of increase 28 days post-transplantation. Three days after progesterone withdrawal, mouse CD45+ cells increased rapidly in number and were significantly greater than human CD45+ cell counts. Mouse CD31+ blood vascular-like structures were detected in both transplanted and host tissues. After progesterone withdrawal, the expression levels of matrix metalloproteinases (MMP) 1, 2, and 9 were increased. In summary, we successfully established a human endometrial xenotransplantation model in SCID mice, based on the results of menstrual-like changes in which MMP-1, 2 and 9 are involved. We showed that leukocytes are originated from in situ proliferation in human xenografts and involved in the occurrence of menstruation. This model will help to further understand the occurrence, growth, and differentiation of the endometrium and the underlying mechanisms of menstruation.     

Depressive Symptoms and Oral Contraceptives

Of 261 women who completed a self-rating scale for measuring depression, 168 were taking oral contraceptives and 93 were using physical methods of contraception. Of the group of women taking oral contraceptives 6·6% were more severely depressed than any of the control group. There was a significant variation in the depth of depression related to the day of the menstrual cycle in the control group. This association was not found in the oral contraceptive group, where premenstrual depression was limited to the one or two days preceding menstruation.Women taking a contraceptive containing lynoestrenol 2·5 mg. and mestranol 0·075 mg. showed a significantly increased incidence of pessimism, feelings of dissatisfaction, crying, and tension, compared with women taking other oral contraceptives and the control group.     

Mifepristone: a novel estrogen-free daily contraceptive pill

When the first synthetic progesterone antagonist (mifepristone) was synthesized over 20 years ago, it was clear that it had a potential as an antifertility agent. Research into the use of antiprogestogens for contraception have concentrated on three general approaches: (1) inhibition of ovulation, (2) inhibition of implantation and (3) disruption of implantation or "menstrual induction". The effect of mifepristone on the ovarian and endometrial cycle depends on dose, timing and frequency of administration. Doses of 10 mg per day or more suppress follicular development and estradiol levels. Ovulatory cycles are maintained in the dose of less than 2 mg although there is increased variability in cycle length. The endometrium shows some minor asynchronous changes, although these are not sufficient to prevent pregnancy. We have chosen to investigate daily doses between 2 and 5 mg which inhibit ovulation and menstruation in over 90% of cycles while still maintaining follicular development and levels of estradiol within the range found during the follicular phase. The endometrium shows proliferative or cystic changes lined by a layer of inactive glandular epithelium set in densely packed stroma. There is, however, an absence of proliferative activity as reflected by a reduced mitotic index and Ki67 staining. These unusual histological appearances are associated with downregulation of PR but a massive upregulation of AR in particularly glandular epithelium. The antiproliferative effect of mifepristone is reassuring suggesting that the risk of atypical hyperplasia due to the effect of prolonged exposure to estrogen unopposed by progesterone is low. In a pilot study, there were no pregnancies in 200 months of exposure in 50 women who used this method as their sole method of contraception. Daily mifepristone could provide a novel contraceptive method which should be devoid of the risks associated with estrogen containing combined oral contraceptive (COC), e.g. venous thromboembolism. The health benefits of avoiding the morbidity associated with menstruation are considerable. Recent surveys suggest that amenorrhoea would be popular with many women.     

Perimenstrual behavior changes among female yellow baboons: Some similarities to premenstrual syndrome (PMS) in women

Although numerous studies have documented changes in the behavior of nonhuman primate females around the time of ovulation, very little attention has been paid to behavior changes around the time of menstruation. Yet such information is obviously relevant to under standing the origins and etiology of the adverse mood and behavior changes experienced premenstrually by many women. Analysis of data obtained during 115 hours of observation on 13 female Amboseli (Kenya) baboons (Papio cynocephalus) during 24 menstrual periods showed that prior to and during the time of menstrual onset, these individuals exhibited distinct changes in their activity budgets, nearest-neighbor distances, and patterns of social interaction. Furthermore, in comparison to females around the time of ovulation, perimenstrual females showed increased rates of agonistic interaction and decreased (but nonzero) rates of sexual interaction with adult males. These premenstrual and perimenstrual behavior changes among female yellow baboons thus show some intriguing similarities to several commonly reported behavioral symptoms of premenstrual syndrome (PMS) in women.     

Menstruation and marital sex

This paper explores differences in sexual behavior between menstrual and nonmenstrual days, using daily report data from 85 husbands and wives for about 100 days each. Most of the men were in graduate school and the wives had a mean education of 16 years. All couples practiced contraception, but not a hormonal or rhythm method. Husband's desire for intercourse was reduced by 6%, the wife's by 19%. A sexual frustration index is arrived at by taking the % of nonintercourse days on which the respondents nevertheless reported wanting intercourse. Husbands showed a frustration index of 22% on nonmenstrual days and 36% on menstrual days. Wives demonstrated a 15% sexual frustration level when not menstruating, 19% during menstruation. The frustration reduction index (arrived at by counting the number of "want intercourse days" on which orgasm occurred without intercourse), was 17% in husbands on menstrual days, 10% on nonmenstrual days; for wives the index was 7% on menstrual days, 6% on nonmenstrual days. The authors conclude that in the highly educated group studied, intercourse and orgasm are reduced during menstruation, in association with impressively less female desire for intercourse during menstruation. The women respond to a resultant potential increase in male sexual frustration by providing the husbands an increase in noncoital orgasm on menstrual days. However, the wives do not experience an increased intercourse frustration level during menstruation and their heterosexual noncoital orgasm rate is relatively stable throughout the cycle. The different patterns of desire levels for husbands and wives may have a biological base, and the different behavior observed represent a sociological compromise.