Male axillary secretions influence women's menstrual cycles: a critique

W. B. Cutler et al. report in the December 1986 issue of Hormones and Behavior (20, 463-473), that women treated with axillary extract from male donors showed reduced variability in menstrual cycle lengths and a reduced proportion of aberrant cycles. The initial samples--seven subjects treated with the male extract and nine subjects treated with blank/ethanol--did not differ significantly in the frequency of aberrant and normal cycles. The cycles of four subjects who were having weekly coital activity were removed from the samples, since coital activity has been shown to be associated with normal-length cycles. The frequency differences of aberrant and normal cycles in the reduced extract and placebo samples were statistically significant. The experiment's conclusions are questionable because (1) the decision to remove the cycles of the four women who had weekly coital activity was not justified by the evidence from this experiment and (2) the researchers lacked an observed preexperimental data base from which to measure changes in the women's cycle lengths.     

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.     

Influence of the Male Axillary Extracts on Regulation of Menstrual Cycles in Women

The effect of male axillary extract on the length and regularity of the menstrual cycle in women was studied in a long-term experiment (9 months). The male secret extract had no statistically significant influence on the menstrual cycle duration in the reproductive-age women (21–45 years) with normal (26–32 days) and regular cycles or in women with abnormally short (<26 days) cycles. In the group of the reproductive-age women with irregular and abnormally long (>32 days) cycles, as well as in the group of the premenopauseage women (46–51 years) with irregular cycles, the secret extract caused a significant shortening of the menstrual cycle as compared to the control. The effect was preserved for at least two months after the exposure completed.     

The laws of Taharat HaMishpacha: potential effects on fertility

The laws of Taharat HaMishpacha (Family purity), which regulate coital activity among Orthodox Jews according to menstrual cycle phase in a population that generally does not use contraception, have potentially important effects on fertility. Analysis of these effects based on menstrual cycle and ovulatory phase lengths for women in the childbearing years shows that the majority of cycles are potentially exposed to coital activity during a fertile period and the increased likelihood of coitus following abstinence has a potentially fertility-enhancing effects. Since most Orthodox Jewish women complete the period of tumah (ritual impurity) and attend the mikveh (a ritual water immersion which marks the end of the cycle) on or before day 14 of the postmenstrual phase, only 22% of cycles are potential sources of diminished fertility as a result of restricted coitus. Any delay in the resumption of sexual relations would result in reduced fecundability for a much larger proportion of cycles. For example, if sexual relations are not resumed until day 15, the proportion of cycles wherein coitus is restricted to the postovulatory phase increases from a maximum of 30% to 41%. Observance of the laws do not greatly diminish the overall fertility of the population assuming that 1) the majority of tumah intervals do not extend beyond 14 days, and 2) coital activity is resumed immediately following return from mikveh. For the individual woman with a predominance of short cycles, delays in conception are probable.     

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.     

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

Menstrual synchrony in human females has previously been demonstrated among women attending a predominantly female university as well as among women attending coeducational universities. In each of these studies, women who spent the most time together were most likely to show the menstrual synchrony. In this experiment, the possibility that substances in axillary secretions might mediate this effect was tested using a prospective, double-blind research design and a combined axillary extract from a group of female donors. Female subjects who reported themselves to have normal (29.5 +/- 3 day) cycles were exposed to the axillary extracts or blank/ethanol for 10 to 13 weeks. Recipients of the axillary extracts showed a significant reduction in "days' difference in menses onset" relative to the donor cycle, no change was evident for recipients of blank/ethanol. These results demonstrate that constituents from the axillary region of donor females can shift the time of menstrual onset of another group to conform with the donors' cycle and that this effect can occur even in the absence of social contact.     

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.     

Female axillary secretions influence women''s menstrual cycles: A critique

Preti, Cutler, Garcia, Huggins, and Lawley report (1986, Horm. Behav. 20, 474-482) that women's menstrual cycles can be modulated with applications of female-derived secretions. An experimental sample of 10 women who reported that they had 29.5 +/- 3 day menstrual cycles was treated on a 22- to 25-day cycle with an extract of axillary secretions from a group of female donors. After two menstrual cycles, the mean absolute difference between the women's menses onsets and the treatment applications decreased significantly. A control sample of 9 women similarly treated with blank/ethanol showed no significant change. Reanalysis of the data indicates that four subjects in the extract sample synchronized with the extract cycles because of "errors" in the extract applications and another four synchronized as a result of experimental design, mathematical properties of cocycling menses onsets, and chance variations. After these factors are accounted for, no evidence suggests that the cycles of the subjects in the extract sample were modulated by the female-derived axillary secretion.     

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.     

Modeling menstrual cycle length using a mixture distribution

In reproductive health studies, epidemiologists are often interested in examining the effects of covariates on menstrual cycle length which is a convenient, noninvasive measure of women's ovarian and reproductive function. Previous literature (Harlow and Zeger, 1991) suggests that the distribution of cycle length is a mixture of a major symmetric distribution and a component featuring a long right tail. Motivated by the shape of this marginal distribution, we propose a mixture distribution for cycle length, representing standard cycles from a Normal distribution and nonstandard cycles from a shifted Weibull distribution. The parameters are estimated using an estimating equation derived from the score function of an independence working model. The fitted mixture distribution agrees well with the distribution estimated using nonparametric approaches. We propose two measures to help determine whether a cycle is standard or nonstandard, developing tools necessary to identify characteristics of the menstrual cycles that are biologically indicative of ovarian dysfunction. We model the effect of a woman's age on the mean and variation of both standard and nonstandard cycle lengths using multiple measurements of women.     

Seasonality on Mood and Length of Menstrual Cycle in Tropical Young Women

In order to know whether seasonal variations affect mood and the length of the menstrual cycle in tropical young women, we have conducted a survey with 200 female students in Hanoi, Vietnam. We used the Vietnamese-translated Self-rating Depression Scale (SDS) for the measurements of their mood. Each of them was given a calendar (from September, 1999 to August, 2000) and was instructed to circle the first day of their menstruation, each month. The results showed that there existed a high prevalence of summer Seasonal Affective Disorder (SAD) and that the length of the menstrual cycle was affected by seasonal change. The average lengths of menstrual cycles were 30.7 ± 0.3 days (mean ± SEM) which is longer than in American young women. The higher occurrence of summer SAD seems to be related to the high ambient temperature during summer in the tropics, influencing their mood.     

Male axillary extracts contain pheromones that affect pulsatile secretion of luteinizing hormone and mood in women recipients

Human underarm secretions, when applied to women recipients, alter the length and timing of the menstrual cycle. These effects are thought to arise from exposure to primer pheromones that are produced in the underarm. Pheromones can affect endocrine (primer) or behavioral (releaser) responses, provide information (signaler), or perhaps even modify emotion or mood (modulator). In this study, we extracted underarm secretions from pads worn by men and placed the extract under the nose of women volunteers while monitoring serum LH and emotion/mood. Pulses of LH are excellent indicators of the release of GnRH from the brain's hypothalamus. In women, the positive influence of GnRH on LH affects the length and timing of the menstrual cycle, which, in turn, affects fertility. Here we show that extracts of male axillary secretions have a direct effect upon LH-pulsing and mood of women. In our subjects, the putative male pheromone(s) advanced the onset of the next peak of LH after its application, reduced tension, and increased relaxation. These results demonstrate that male axillary secretions contain one or more constituents that act as primer and modulator pheromones.     

Psychosocial stress and the menstrual cycle.

The relationship between mood states, urinary stress hormone output (adrenaline, noradrenaline and cortisol) and adequacy of the menstrual cycle was examined in 120 recorded non-conception cycles from 34 women. It was hypothesized that women with higher stress levels would be more likely to experience abnormal cycles and that within women higher stress levels would positively relate to follicular phase length and inversely relate to luteal phase length. There was a non-significant trend for women to report higher stress levels during oligomenorrhoeic and unclear cycles compared with normal cycles. Analysis of covariance indicated that there was no consistent relationship between the measures of stress used here and follicular or luteal phase length within women. There was also no consistent pattern of relationship between reported mood states and stress hormone excretion within women. Further research is warranted to understand the role of stress and subtle menstrual cycle abnormalities in female fertility.     

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.     

Reproductive function in aged female chimpanzees.

Reproductive function was evaluated in ten female chimpanzees (Pan troglodytes) aged 35-48 years. Forty-eight years is the longevity record for the chimpanzee. Data on cycle frequency and duration was available for seven animals. Most were cycling regularly until death, and all had experienced at least one menstrual cycle within one year of death. After exclusion of periods when the animals were pregnant or in postpartum amenorrhea, the mean cycle frequency (+/- standard error)/year was 9.54 +/- 0.20 in seven animals aged 15-25 (432 cycles analyzed) compared to 8.6 +/- 0.76 in the same animals at age 35 + years (405 cycles analyzed); this effect approached significance (p = 0.072, Mann-Whitney U-test). Cycle length of 16 cycles in each of seven animals aged 15-25 was 32.23 +/- 0.38 days. The same animals when aged over 35 had mean cycle lengths of 35.59 +/- 0.73. This difference was not significant, although cycle lengths clearly increased with age in some individual animals. In five aged animals for which mating data was available, appropriate exposure to a male occurred in 52 cycles, but only two pregnancies occurred; one pregnancy resulted in a live birth at age 38, the other in a stillbirth at age 40. This conception rate was 3.85% compared with 20% in the same animals aged 15-25. These data suggest greatly reduced fertility after age 35, although menstrual cycle frequency remained high. The persistence of menstrual cyclicity until death, which occurred due to natural causes at latest in the fifth decade, is in striking contrast to the human female in which menopause occurs in the fifth decade and death is often postponed for several more decades.     

Reproductive endocrine effects of intranasal administration of norethisterone to adult female rhesus monkeys (Macaca mulatta)

Intranasal administration of norethisterone at a daily dose of 9 micrograms between Days 5 and 14 of the menstrual cycles blocked ovulation in 10 out of 17 adult female monkeys. Serum concentrations of hormones indicated that ovulation was blocked due to a suppression of the mid-cycle, oestradiol-induced LH surge. Ovarian follicular activity in the treated menstrual cycles was not affected by norethisterone but there was a marked delay in the onset of the mid-cycle oestradiol surge in most of the treated animals. The duration of the menstrual cycle length after the oestradiol peak was significantly reduced in all the treated monkeys, indicative of a shortened luteal phase.     

Breeding of African green monkeys (Cercopithecus aethiops) under indoor individually-caged conditions.

This paper reports the results of reproduction with 45 wild African green monkeys (Cercopithecus aethiops) (36 females and 9 males) during the nine years from 1981 to 1989 under indoor individually-caged conditions. In 206 cases of menstruation observed, menstrual discharge lasted for 2.5 +/- 1.2 days in cycles of 22-48 days, and the length of each menstrual cycle was 31.2 +/- 6.5 days. Females who had regular menstrual cycles were subjected to "one-to-one timed mating"; females and males were put together on a one-to-one basis daily only for a certain period of time on and after the day of ovulation. Females who had irregular menstrual cycles or had no menstruation were subjected to "every-other-day mating"; females and males were put together on a one-to-one basis every other day for at least 16 weeks. The pregnancy rate (No. of pregnant females/No. of mated females) by one-to-one timed mating was 48.9% (116/237); 2.0 mating trials were needed to obtain one case of pregnancy. On the other hand, the pregnancy rate (No. of pregnant females/No. of mating trials) by every-other-day mating was 96% (48/50). Females who delivered normally totaled 129. The mean gestation period was 165 days when males, weighing 343 g on average at birth, were delivered, and 166 days when females, weighing 318 g on average at birth, were delivered. The male and female newborns were nursed for 131 and 138 days, respectively, on average. Details are summarized in Table 3. This paper also reports 23 cases of abortion, 6 stillbirths, and 6 cases of Caesarean section, by which three live fetuses and three dead fetuses were obtained.     

A joint mixed effects dispersion model for menstrual cycle length and time-to-pregnancy

Menstrual cycle patterns are often used as indicators of female fecundity and are associated with hormonally dependent diseases such as breast cancer. A question of considerable interest is in identifying menstrual cycle patterns, and their association with fecundity. A source of data for addressing this question is prospective pregnancy studies that collect detailed information on reproductive aged women. However, methodological challenges exist in ascertaining the association between these two processes as the number of longitudinally measured menstrual cycles is relatively small and informatively censored by time to pregnancy (TTP), as well as the cycle length distribution being highly skewed. We propose a joint modeling approach with a mixed effects dispersion model for the menstrual cycle lengths and a discrete survival model for TTP to address this question. This allows us to assess the effect of important characteristics of menstrual cycle that are associated with fecundity. We are also able to assess the effect of fecundity predictors such as age at menarche, age, and parity on both these processes. An advantage of the proposed approach is the prediction of the TTP, thus allowing us to study the efficacy of menstrual cycle characteristics in predicting fecundity. We analyze two prospective pregnancy studies to illustrate our proposed method by building a model based on the Oxford Conception Study, and predicting for the New York State Angler Cohort Prospective Pregnancy Study. Our analysis has relevant findings for assessing fecundity.     

Failure of daily injections of ketamine HCL to adversely alter menstrual cycle length, blood estrogen, and progesterone levels in the rhesus monkey.

Failure of daily injections of ketamine hydrogen chloride (HCL) to adversely alter menstrual cycle length, blood estorgen, and progesterone levels in the rhesus monkey is reported. The study was carried out with 30 adult female monkeys to determine the effects of daily administration of 8-10 mg ketamine HCL/kg. In physically restrained control monkeys there were 14 of 25 ovulatory cycles and inketamine-treated monkeys there were 28 of 32 ovulatory cycles. Menstrual cycle length was the same in both groups. The levels and time course of estrogen and progesterone levels were the same in the ovulatory cycles of both groups. In 30% of the control cycles and in 25% of the ketamine-treated there were luteal phases in which the preovulatory estrogen levels were normal and in which the luteal-phase progesterone levels were low and variable 6-8 days after the preovulatory surge. It is concluded that the daily use of ketamine HCL does not markedly alter menstrual cycle length, or serum estrogen or progesterone levels throughout the menstrual cycle. The incidence of anovulatory cycles and premature menstrual induction was reduced probably by reducing the stress of restraining the monkey for the purpose of taking a blood sample.     

Sporadic sexual behavior and menstrual cycle length in women

In an initial study of 248 university students prospective double-blind monitoring of sexual behavior and menses onsets showed that sporadic (less than regular weekly) sexual activity was associated with aberrant menstrual cycle lengths. This study examines the sample of sporadically active women for behavioral correlates of aberrant cycle lengths. It is shown that women reporting a high frequency of sexual activity (though in a sporadic pattern) showed a higher incidence of aberrant cycle lengths than women reporting a low frequency of sporadic coitus. Stable ongoing sexual behavior patterns appear to associate with a different endocrine background than less stable, sporadic sexual patterns.