Physical activity of adult female rhesus monkeys (Macaca mulatta) across the menstrual cycle

Physical activity is an important physiological variable impacting on a number of systems in the body. In rodents and several species of domestic animals, levels of physical activity have been reported to vary across the estrous cycle; however, it is unclear whether such changes in activity occur in women and other primates across the menstrual cycle. To determine whether significant changes in activity occur over the menstrual cycle, we continuously measured physical activity in seven adult female rhesus monkeys by accelerometry over the course of one menstrual cycle. Monkeys were checked daily for menses, and daily blood samples were collected for measurement of reproductive hormones. All monkeys displayed ovulatory menstrual cycles, ranging from 23 to 31 days in length. There was a significant increase in estradiol from the early follicular phase to the day of ovulation (F(1.005,5.023) = 40.060, P = 0.001). However, there was no significant change in physical activity across the menstrual cycle (F(2,12) = 0.225, P = 0.802), with activity levels being similar in the early follicular phase, on the day of the preovulatory rise in estradiol and during the midluteal phase. Moreover, the physical activity of these monkeys was not outside the range of physical activity that we measured in 15 ovariectomized monkeys. We conclude that, in primates, physical activity does not change across the menstrual cycle and is not influenced by physiological changes in circulating estradiol. This finding will allow investigators to record physical activity in female primates without the concern of controlling for the phase of the menstrual cycle.     

Copeptin Levels Remain Unchanged during the Menstrual Cycle

Background

Copeptin, a surrogate marker for arginin vasopressin production, is evaluated as an osmo-dependent stress and inflammatory biomarker in different diseases. We investigated copeptin during the menstrual cycle and its relationship to sex hormones, markers of subclinical inflammation and estimates of body fluid.

Methods

In 15 healthy women with regular menstrual cycles, blood was drawn on fifteen defined days of their menstrual cycle and was assayed for copeptin, progesterone, estradiol, luteinizing hormone, high-sensitive C-reactive protein, tumor necrosis factor-alpha and procalcitonin. Symptoms of fluid retention were assessed on each visit, and bio impedance analysis was measured thrice to estimate body fluid changes. Mixed linear model analysis was performed to assess the changes of copeptin across the menstrual cycle and the relationship of sex hormones, markers of subclinical inflammation and estimates of body fluid with copeptin.

Results

Copeptin levels did not significantly change during the menstrual cycle (p = 0.16). Throughout the menstrual cycle, changes in estradiol (p = 0.002) and in the physical premenstrual symptom score (p = 0.01) were positively related to copeptin, but changes in other sex hormones, in markers of subclinical inflammation or in bio impedance analysis-estimated body fluid were not (all p = ns).

Conclusion

Although changes in estradiol and the physical premenstrual symptom score appear to be related to copeptin changes, copeptin does not significantly change during the menstrual cycle.     

Wild fulvous fruit bats (Rousettus leschenaulti) exhibit human-like menstrual cycle

We investigated the menstrual cycle of wild fulvous fruit bats (Rousettus leschenaulti), focusing on changes in the endometrial and ovarian structure and pituitary and steroid hormones. The menstrual cycle lasts for 33 days in bats studied in their natural habitat and in captivity. Vaginal bleeding was restricted to a single day (Day 1). A preovulatory follicle was found in the ovary on Day 18 when the levels of LH and FSH reached their maxima, accompanied by a thickened endometrium. On Day 24, serum levels of progesterone and estradiol-17 were also maximal, and uterine glands increased in size. After that, the levels of progesterone dropped precipitously, leading to menstrual bleeding. Both the morphologic and hormonal changes observed in fulvous fruit bats during the menstrual cycle resemble similar changes in humans. Fulvous fruit bats may be useful nonprimate laboratory models to study menstruation and menstrual dysfunction.     

The menstrual cycle and its effect on behaviour in the Talapoin monkey (Miopithecus talapoin)

The menstrual cycles of 14 captive Talapoin monkeys ( Miopithecus talapoin ) were studied by making serial observations on the vaginal smears and sexual skin swellings for up to 15 months. Twelve of these females menstruated and the mean duration of their cycle was32–9 days (95% confidence limits 28.0-37.7). The corresponding value for the seven most regular females was 33.0 days (29.1-36.8). There were rhythmic changes in the vaginal smears and sexual skin during the menstrual cycle. Maximum cornification of the smears and maximum sexual skin swelling were observed at midcycle; the sexual skin deflated and the smear became less cornified during the luteal phase. The follicular phase—i.e. from menstruation to maximum skin swelling lasted 20.4 days with a wide distribution, in contrast to the mean duration of the luteal phase (13.7 days) which showed a pronounced peak at 14 days. The menstrual cycle of the talapoin thus resembles those of certain other Old World monkeys that exhibit perineal sexual skin swelling.
Sexual behaviour of the male and female was maximal near the female's midcycle and minimal during the luteal phase, with intermediate values in the follicular phase. The males were most aggressive towards other females of the group when one female was at midcycle; there were no consistent changes in aggression between the male and the female herself. The number of times one animal looks at another (a characteristic behaviour pattern in talapoins) was measured and occurred most often at midcycle, but other preliminary observations indicated a more pronounced correlation between this behaviour pattern and an animal's position in the hierarchy.     

Human axillary secretions influence women''s menstrual cycles: The role of donor extract from men

Menstrual cycle lengths of 29.5 +/- 3 days ("normal cycles") are more frequent in women who have weekly coital activity than in women who do not. In order to investigate potential mechanisms controlling the association between heterosexual activity and menstrual cycle length, and in light of the nonhuman literature suggesting that a chemical signal from males could be involved, menstrual cycle lengths of nulliparous women were evaluated following regular application of axillary extract from donor males. Compared to controls receiving only blank/ethanol applications, women receiving axillary extracts for 12.5 to 14.5 weeks showed the following changes: a reduced incidence in variability of cycle lengths; and a reduced proportion of aberrant length cycles.     

圈养条件下黑猩猩月经、排卵和妊娠周期

排卵期和妊娠期与月经周期紧密相关,监测月经周期对圈养黑猩猩（Pan troglodytes）的繁殖有着重要意义。本研究对上海动物园饲养的8只雌性黑猩猩2002年以来的月经周期记录进行统计分析,并对2只成年雌性黑猩猩共60 d尿液中促黄体生成素进行检测。黑猩猩月经周期平均为（33.5 ± 5.3）d,经期平均为（1.6 ± 1.1）d,妊娠期平均为（226.9 ± 17.3）d,产单胎和双胎有极显著差异;促黄体生成素在发情高峰期出现了峰值。     

Pattern of menstrual cycle length in South Indian women: A prospective study

Abstract

Data on 8,308 menstrual cycles from 1,740 South Indian women prospectively recorded were analyzed to identify the effect of age on menstrual cycle length. The distribution was skewed to the right with the mean (SD) cycle length of 31.8 (6.7) days. The range of 25–40 days constituted 10–82 per cent of menstrual cycle lengths. In no age group did 28‐day cycles occur in more than 9 per cent of women. Variability as measured by the standard deviation was high among those below 19 years of age, stabilized during 25–39 years, and then increased in women aged 40 years or more. The findings are discussed in the light of other studies and possible implications in fertility control programs.     

Changes in plasma adrenomedullin levels during the menstrual cycle

We investigated whether the levels of adrenomedullin, a novel peptide produced by several tissues, including the pituitary gland, change during the ovarian cycle. We studied 13 healthy women with regular menstrual cycles. Plasma samples were collected at 7, 14, 21 and 28 days of the ovarian cycle and assayed for adrenomedullin 1-52 using a specific RIA. LH, FSH, 17beta-estradiol, and progesterone concentrations were also determined. The adrenomedullin profile during ovarian cycle was similar to that of LH; plasma adrenomedullin increased from 10.9 pg/ml at the 7th day to 15.1 pg/ml at the 14th, and decreased to 8.5 pg/ml in the subsequent menses. The changes in plasma adrenomedullin were related to changes in LH and 17beta-estradiol. The cause of the increase in adrenomedullin levels during the late follicular phase of the menstrual cycle is not clear. Since it has been demonstrated that adrenomedullin is involved in the regulation of hypothalamus-pituitary-adrenal gland and its secretion is regulated by sex hormones we speculate that adrenomedullin could also play a role in regulating the hypothalamus-pituitary-ovary feedback. Alternatively it may be involved in the regulation of fluid and electrolyte homeostasis during the menstrual cycle.     

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.     

Prolactin suppresses GnRH but not TSH secretion

BACKGROUND/AIMS: In animal models, prolactin increases tuberoinfundibular dopamine turnover, which has been demonstrated to suppress both hypothalamic GnRH and pituitary TSH secretion. To test the hypothesis that prolactin suppresses GnRH and TSH secretion in women, as preliminary evidence that a short-feedback dopamine loop also operates in the human, the effect of hyperprolactinemia on GnRH and TSH secretion was examined. METHODS: Subjects (n=6) underwent blood sampling every 10 min in the follicular phase of a control cycle and during a 12-hour recombinant human prolactin (r-hPRL) infusion preceded by 7 days of twice-daily subcutaneous r-hPRL injections. LH and TSH pulse patterns and menstrual cycle parameters were measured. RESULTS: During the 7 days of r-hPRL administration, baseline prolactin increased from 16.0+/-3.0 to 101.6+/-11.6 microg/l, with a further increase to 253.7+/-27.7 microg/l during the 12-hour infusion. LH pulse frequency decreased (8.7+/-1.0 to 6.0+/-1.0 pulses/12 h; p<0.05) with r-hPRL administration, but there were no changes in LH pulse amplitude or mean LH levels. There were also no changes in TSH pulse frequency, mean or peak TSH. The decreased LH pulse frequency did not affect estradiol, inhibin A or B concentrations, or menstrual cycle length. CONCLUSION: These studies demonstrate that hyperprolactinemia suppresses pulsatile LH secretion but not TSH secretion and suggest that GnRH secretion is sensitive to hyperprolactinemia, but that TSH secretion is not. These data further suggest that the degree of GnRH disruption after 7 days of hyperprolactinemia is insufficient to disrupt menstrual cyclicity.     

Relation between surgery-induced prolactin increase and the menstrual cycle phase at time of surgery in premenopausal breast cancer

It has been suggested that both the menstrual cycle phase and postoperative changes in prolactin (PRL) secretion at the time of surgery may influence the prognosis of breast cancer. The present study was carried out to evaluate the relation between menstrual cycle period and surgery-induced PRL variations. We evaluated 32 premenopausal women with operable breast carcinoma; 17 were in perimenstrual phase (days 1-6 and 21-28) and 15 were in the mid-cycle (days 7-20) period at the time of surgery. To investigate serum levels of PRL, venous blood samples were collected before and 7 days after surgery. Postoperative hyperprolactinemia occurred in 17/32 patients and it was statistically more frequent in patients surgically treated during the perimenstrual phase than in the mid-cycle phase (12/17 vs 5/15; p less than 0.05), while no other parameter (including axillary node and estrogen receptor status) showed a significant influence on hyperprolactinemia rate. The results suggest that in premenopausal breast cancer patients surgery-induced hyperprolactinemia may be influenced by the menstrual cycle phase at the time of surgery.     

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.     

Menstrual cycle characteristics and predictability of ovulation of Bhutia women in Sikkim, India

Although a woman's menstrual history can have significant implications for health outcomes, few studies have examined menstrual cycle variability in non-western, non-clinically based populations. This study presents menstrual cycle characteristics from Bhutia women living in Gangtok, Sikkim, India. The Bhutia are one of two indigenous populations residing in this small, northeastern state of India. A total of 1067 cycles were recorded by 200 Bhutia women over the course of 12 months. Mean cycle length in this population was similar to reported mean cycle lengths for populations in the U.S (30 days vs. 28 days). Menstrual cycles in this sample were highly variable with most women experiencing more than one short or long menstrual cycle. The frequency of irregular menstrual cycles experienced by individuals also varied significantly by season. A body mass index (BMI) above or below the WHO defined normal range was associated with higher rates of irregular cycles. Leutenizing hormone (LH) and follicle stimulating hormone (FSH) levels were also determined from urine samples collected just before mid-cycle, based on median cycle lengths. Although menstrual cycles in this sample were highly variable, median cycle length was still useful in predicting timing of the pre-ovulatory hormone surges of LH and FSH. Frequency of irregular cycles did impact the successful capture of the LH and FSH peak values.     

Menstrual Phase Response to Nocturnal Light

The aims of the study were to test whether nocturnal white light can normalize menstrual cycles in oligomenorrheic women, and whether the phase of the menstrual cycle in which light is given is important for the shortening effect. Twenty-five women with long menstrual cycles (35.9–53.4 days on average) were treated for 1–3 cycles, each of which was preceded and followed by at least two untreated cycles. Treatments were 100 watt bedside lights administered for 5 consecutive nights. They centered at three different phases of the menstrual cycle: 6–7th, 14–17th or 23–25th days of the treated cycle (early, middle or late treatment, respectively). On average, the treatment cycle lengths were modestly, but significantly reduced compared to the duration of baseline cycles (more than 11 %). The difference in the effects of the early, middle and late treatment was not significant. However, if middle or late treatments were administered in the latter half of the interval between the menstrual cycle onset and probable time of ovulation, reductions of the treated cycle length were substantial (more than 20 %, resulting in cycles less than 33 days on average; p &lt; 0.001). Other treatments produced only weak (up to 7 %), if any, cycle reductions. Moreover, we found a strong correlation (p &lt; 0.001) between the duration of baseline cycle and differential effect of middle treatment (compared to early or late treatment). Middle treatments reduced treated cycle duration to the normal range in the subjects with shorter mean baseline cycles (&lt;42 days), while in the subjects with longer duration of baseline cycle the shortening effect was produced by late treatments (p = 0.005 and p = 0.001, respectively). The results support the suggestion that a bedside lamp used on nights prior to ovulation can cause reduction of long menstrual cycles.     

Non-Advertized does not Mean Concealed: Body Odour Changes across the Human Menstrual Cycle

Females of a number of primate species display their fertile period by behavioural and/or morphological changes. Traditionally, the fertile period in human females has been considered to be concealed. However, this presumption has rarely been tested. One of the possible mechanisms for assessing menstrual cycle phase is through the sense of smell. In this study possible changes in odour across the menstrual cycle were investigated. Samples of body odour were acquired from 12 women (aged 19–27 yr), none of whom were using hormonal contraceptives. Samples were collected using cotton pads worn in the armpit for 24 h, from the menstrual, follicular and luteal cycle phases. Our experimental sample of 42 males (age 19–34 yr) repeatedly rated these odour samples for their intensity, pleasantness, attractiveness and femininity. Raw subjective smell ratings from each man were transformed to z‐scores. Subsequently, these z‐scores were tested by the general linear mixed‐model analysis (PROC MIXED, SAS) with the female's ID nested within the subject's ID as a random factor to account for the repeated measures of the subjects. Significant changes across the cycle were found for ratings of pleasantness [F_(2,689) = 702; p = 0.001], attractiveness [F(2,546) = 6.35; p = 0.002] and intensity [F(2,530) = 3.57; p = 0.028]. Odour from women in the follicular (i.e. fertile) phase was rated as the least intense and the most attractive. Subsequent post hoc analysis revealed significant differences in intensity, pleasantness and attractiveness between the menstrual phase and the follicular phase, and in pleasantness and attractiveness between the menstrual and luteal phases. Significant difference between the follicular and the luteal phase was found only for attractiveness. Our results suggest that men can potentially use smell as a mechanism for monitoring menstrual cycle phase in current or prospective sexual partners. Therefore, the fertile period in humans should be considered non‐advertized, rather than concealed.     

Disturbance of the Duration in the Menstrual Cycle under the Influence of Tight Clothing

We investigated the influence of skin pressure by clothing on the duration of menstrual cycle with 33 young adult women. The average age was 19.9 ± 2.1 years (mean ± SD), stature 159.5 ± 5.6cm and body mass 50.9 ± 5.5kg. Thirty-three women participated as subjects. They wore their usual clothing including foundation garments, panty stocking, pants or skirt and T-shirt or blouse and cardigan for the first 4 months from December to March ('Tight 1'). For the second 4 months from April to July, the women wore loose clothes, i.e., they did not wear foundation garments at home. Skirt and jeans were worn loosely ('Loose'). For the last 4 months, from August to November, they wore their clothes as tightly as possible, compared to 'Tight 1' ('Tight 2'). Each participant marked the first day of the occurrence of menses in the pocket diary throughout the year. The main results were summarized as follows: 1) The average duration of the menstrual cycle was 44.2 ± 14.9 days (mean ±) in 'Tight 1', 30.4 ± 3.0 days in 'Loose' and 47.4 ± 22.7 days in 'Tight 2'. 2) The number of months when the menses did not occur was 38 for 'Tight 1', 6 for 'Loose' and 40 for 'Tight 2'. 3). The number of participants who had a duration of the menstrual cycles for more than 40 days, was 25 participants for 'Tight', 10 for 'Loose' and 29 for 'Tight'. It can be concluded that skin pressure by clothing could disturb the duration in the menstrual cycle.     

Disturbance of the Duration in the Menstrual Cycle under the Influence of Tight Clothing

We investigated the influence of skin pressure by clothing on the duration of menstrual cycle with 33 young adult women. The average age was 19.9 ± 2.1 years (mean ± SD), stature 159.5 ± 5.6cm and body mass 50.9 ± 5.5kg. Thirty-three women participated as subjects. They wore their usual clothing including foundation garments, panty stocking, pants or skirt and T-shirt or blouse and cardigan for the first 4 months from December to March (‘Tight 1’). For the second 4 months from April to July, the women wore loose clothes, i.e., they did not wear foundation garments at home. Skirt and jeans were worn loosely (‘Loose’). For the last 4 months, from August to November, they wore their clothes as tightly as possible, compared to ‘Tight 1’ (‘Tight 2’). Each participant marked the first day of the occurrence of menses in the pocket diary throughout the year. The main results were summarized as follows: 1) The average duration of the menstrual cycle was 44.2 ± 14.9 days (mean ±) in ‘Tight 1’, 30.4 ± 3.0 days in ‘Loose’ and 47.4 ± 22.7 days in ‘Tight 2’. 2) The number of months when the menses did not occur was 38 for ‘Tight 1’, 6 for ‘Loose’ and 40 for ‘Tight 2’. 3). The number of participants who had a duration of the menstrual cycles for more than 40 days, was 25 participants for ‘Tight’, 10 for ‘Loose’ and 29 for ‘Tight’. It can be concluded that skin pressure by clothing could disturb the duration in the menstrual cycle.     

Conflict,displacement activities,and menstrual cycle in long-tailed macaques

This study was aimed at testing whether the female menstrual cycle is associated with changes in social tension experienced by eight heterosexual pairs of long-tailed macaques (Macaca fascicularis). Displacement activities were considered as a behavioral measure of social tension and recorded during the periovulatory and the menstrual flow phases of the cycle. While male yawning and body shake underwent nonsignificant increases, male autogrooming and scratching increased significantly during the periovulatory phase. Female displacement activities did not show any significant difference between the two phases. Male and female socio-sexual behavior was not affected by the menstrual cycle. These results suggest that the male conflictual state, but not the female one, is affected by female menstrual cycle.     

Pattern of menstrual cycle length in south Indian women: a prospective study.

Data on 8,308 menstrual cycles from 1,740 South Indian women prospectively recorded were analyzed to identify the effect of age on menstrual cycle length. The distribution was skewed to the right with the mean (SD) cycle length of 31.8 (6.7) days. The range of 25-40 days constituted 10-82 per cent of menstrual cycle lengths. In no age group did 28-day cycles occur in more than 9 per cent of women. Variability as measured by the standard deviation was high among those below 19 years of age, stabilized during 25-39 years, and then increased in women aged 40 years or more. The findings are discussed in the light of other studies and possible implications in fertility control programs.     

Menstrual cycle and some other related aspects of Japanese monkeys (Macaca fuscata)

The menstrual cycle and some other related aspects of Japanese monkeys (Macaca fuscata) were dealt with in this paper. Almost all the monkeys had regular menstrual cycles only in the mating season, and had no menstrual cycles, or only irregular ones, in the non-mating season. The average length of the menstrual cycle in the mating season was 26.3 ±5.4 days. Many monkeys had a tendency to have their own individual and relatively regular cycles. Ninety out of 108 monkeys kept in the air-conditioned quarters for five years showed “periodical changes” essentially coincident with the changes of outdoor season, and this fact suggests that the rhythm of the seasonal change of Japanese monkeys remains for a relatively long period even if the monkeys are kept in air-conditioned quarters where room temperature and lighting are kept constant throughout the year. Vaginal smear, cervical mucus, sexual skin, etc. were observed in relation to ovulation. These characters showed cyclic changes with menstrual cycles in about half of all cases observed, but ovulation occurred even in the cases in which no cyclic change was observed. Therefore, it was not necessarily easy to estimate the ovulation by observing these characters.