Ovulatory shifts in human female ornamentation: near ovulation, women dress to impress

Humans differ from many other primates in the apparent absence of obvious advertisements of fertility within the ovulatory cycle. However, recent studies demonstrate increases in women's sexual motivation near ovulation, raising the question of whether human ovulation could be marked by observable changes in overt behavior. Using a sample of 30 partnered women photographed at high and low fertility cycle phases, we show that readily-observable behaviors - self-grooming and ornamentation through attractive choice of dress - increase during the fertile phase of the ovulatory cycle. At above-chance levels, 42 judges selected photographs of women in their fertile (59.5%) rather than luteal phase (40.5%) as "trying to look more attractive." Moreover, the closer women were to ovulation when photographed in the fertile window, the more frequently their fertile photograph was chosen. Although an emerging literature indicates a variety of changes in women across the cycle, the ornamentation effect is striking in both its magnitude and its status as an overt behavioral difference that can be easily observed by others. It may help explain the previously documented finding that men's mate retention efforts increase as their partners approach ovulation.     

Behavioral indices of estrus in a group of captive African elephants (Loxodonta africana)

This study investigated behavioral signals of estrus by systematically monitoring the interactions of one male with four female African elephants housed in a naturalistic outdoor enclosure at Disney's Animal Kingdom over a period of 11 months. We measured changes in five spatial behaviors and 22 tactile‐contact behaviors, as well as changes in serum progestagen and LH concentrations, across three ovarian cycles for each female. Two females did not cycle during the study. Three different phases of the ovarian cycle were identified: mid luteal, anovulatory follicular, ovulatory follicular. The male followed more and carried out more genital inspections, flehmen, and trunk‐to‐mouth behaviors toward cycling females during their ovulatory phase. Genital inspections by the male peaked above baseline levels on the day of an LH surge, and up to 9 days before, in both cycling females and, thus, might be a useful behavioral index of estrus. The male also carried out more genital inspections, flehmen, and trunk touches to the back leg toward ovulatory cycling than noncycling females. Overall, our results indicated that: 1) a single subadult African elephant male could discriminate two females in the ovulatory phase of their cycle (i.e., during the 3 weeks preceding ovulation) from the mid luteal phase; 2) the male also discriminated two cycling females in the ovulatory and anovulatory follicular phases from two noncycling females; 3) two females in the ovulatory phase of the cycle displayed a greater variety of tactile‐contact behavior toward the male compared to the other cycle phases. Zoo Biol 0:1–19, 2005. © 2005 Wiley‐Liss, Inc.     

Ovulation-inhibiting properties of Org OD 14

Org OD 14 has recently been shown to be an interesting new steroid for the treatment of menopausal women. In view of the importance of treatment of perimenopausal women, in whom ovulation might occur, the aim of the present study was to assess whether or not Org OD 14, administered orally in a daily dose of 2.5 mg for 21 days, inhibits ovulation. Sixteen healthy female volunteers, aged 20-34 years and with established ovulatory cycles, were studied during a control cycle and a treatment cycle. Daily measurements of the plasma levels of FSH, LH, E2, P and PRL were made. Endometrial specimens were obtained from nine of the volunteers between 23rd and 25th day of both cycles. The criteria for an ovulatory cycle were: (1) mid-cycle FSH, LH and E2 peaks; (2) criteria (1) followed by a rise in the P levels of greater than 10 ng/ml; (3) a luteal phase of at least 12 days; (4) biphasic behaviour of E2; and, (5) secretory endometrium on days 23-25 of the cycle. All control cycles were ovulatory. During the treatment the mid-cycle FSH, LH and E2 peaks disappeared, and P levels remained very low. PRL levels showed an occasional moderate rise in some of the volunteers. Endometrial specimens showed a secretory pattern during the control cycle, and different degrees of proliferation during the treatment cycle in all nine volunteers. It was concluded that Org OD 14 inhibited ovulation in all 16 volunteers.     

Effects of partner conception risk phase on male perception of dominance in faces

Several studies have suggested that women may prefer to engage in extra-pair copulations with males who appear dominant and to do so near ovulation. While there is some evidence that males are more jealous of dominant rivals and more proprietary when their partners are near ovulation, there is none that suggests the existence of counterstrategic perceptual shifts that mirror those seen in women. We provide such evidence here. Composites of male faces that were either high or low in rated dominance were presented to male participants who provided ratings of dominance. A three-way interaction between stimulus-face dominance, partner conception risk phase, and partner oral contraceptive use was found; men whose partners did not use an oral contraceptive and were in the high conception risk phase of their cycle displayed increased dominance ratings of high-dominance male faces. We conclude that males have evolved counterstrategies to deal with female infidelity that include an overattribution of dominance to those rivals most likely to present a threat at times when that threat is greatest. This overattribution is likely to lead to increases in jealousy and mate-retention behaviors.     

The Impact of Menstrual Cycle Phase on Economic Choice and Rationality

It is well known that hormones affect both brain and behavior, but less is known about the extent to which hormones affect economic decision-making. Numerous studies demonstrate gender differences in attitudes to risk and loss in financial decision-making, often finding that women are more loss and risk averse than men. It is unclear what drives these effects and whether cyclically varying hormonal differences between men and women contribute to differences in economic preferences. We focus here on how economic rationality and preferences change as a function of menstrual cycle phase in women. We tested adherence to the Generalized Axiom of Revealed Preference (GARP), the standard test of economic rationality. If choices satisfy GARP then there exists a well-behaved utility function that the subject’s decisions maximize. We also examined whether risk attitudes and loss aversion change as a function of cycle phase. We found that, despite large fluctuations in hormone levels, women are as technically rational in their choice behavior as their male counterparts at all phases of the menstrual cycle. However, women are more likely to choose risky options that can lead to potential losses while ovulating; during ovulation women are less loss averse than men and therefore more economically rational than men in this regard. These findings may have market-level implications: ovulating women more effectively maximize expected value than do other groups.     

Changes in Sleep Time and Sleep Quality across the Ovulatory Cycle as a Function of Fertility and Partner Attractiveness

Research suggests that near ovulation women tend to consume fewer calories and engage in more physical activity; they are judged to be more attractive, express greater preferences for masculine and symmetrical men, and experience increases in sexual desire for men other than their primary partners. Some of these cycle phase shifts are moderated by partner attractiveness and interpreted as strategic responses to women''s current reproductive context. The present study investigated changes in sleep across the ovulatory cycle, based on the hypothesis that changes in sleep may reflect ancestral strategic shifts of time and energy toward reproductive activities. Participants completed a 32-day daily diary in which they recorded their sleep time and quality for each day, yielding over 1,000 observations of sleep time and quality. Results indicated that, when the probability of conception was high, women partnered with less attractive men slept more, while women with more attractive partners slept less.     

Intersexual conflict across women's ovulatory cycle

A growing literature shows that the features women find particularly attractive in men vary across the ovulatory cycle. Women furthermore appear to more frequently report attraction to men other than primary partners when they are fertile in their cycle than in the infertile luteal phase. Previous studies have shown that men are more vigilant of or attentive to their primary partners during the fertile phase compared to the luteal phase. This study had several aims: First, to replicate and extend previous findings concerning men's vigilance of partners using male as well as female reports of men's behavior; second, to examine changes in women's behavior toward partners across the cycle; third, to examine ways in which women resist men's attempts to mate-guard across the cycle. Results indicate that (a) men are particularly self-assertive toward partners when their partners are fertile; (b) similarly, women are especially self-assertive toward partners when they are fertile; (c) women report engaging in more behaviors that resist male vigilance and mate guarding when they are fertile, especially in ways that are unobservable to male partners; and (d) these effects are especially strong when women themselves report greater attraction to men other than partners when they are fertile, compared to the luteal phase.     

Modifications of EEG Activity Related to Perception of Emotionally Colored,Erotic, and Neutral Pictures in Women during Different Phases of the Ovulatory (Menstrual) Cycle

We studied modifications of EEG activity related to perception of visual stimuli (pictures) of the International Affective Picture System (IAPS) in women during different phases of the ovulatory (menstrual) cycle. We found that the woman’s brain is most intensely activated by both emotionally negative and positive visual stimuli during the follicular phase of the ovulatory cycle, while such activation is minimum during ovulation per se. Upon the action of neutral stimuli, cerebral activation was the most intense during the lutein phase (compared with that within other phases); manifestations of activation were concentrated in the right hemisphere. Cognitive and emotional components of perception of affective pictures were expressed to a greatest extent in the course of viewing positive stimuli during the follicular phase. Perception of emotionally pleasant stimuli during other phases was accompanied by lateralization of activation of sensory and analytical processes in the left hemisphere during the ovulatory phase and in the right hemisphere within the lutein phase. The viewing of emotionally negative pictures during the follicular phase led to a rise in the power of theta oscillations in the left frontal region and also to depression of the alpha activity in central/parietal parts of the left hemisphere, which can result from aggravation of anxiety and verbally shaped disturbing ideas upon the action of such stimuli. Presentation of erotically colored visual stimuli caused the most intense changes in the EEG, which depended on the phases of the ovulatory cycle, during post-stimulation time interval but not during the viewing of pictures itself.     

Ovulation Prevalence in Women with Spontaneous Normal-Length Menstrual Cycles – A Population-Based Cohort from HUNT3, Norway

Background

Ovulatory menstrual cycles are essential for women’s fertility and needed to prevent bone loss. There is a medical/cultural expectation that clinically normal menstrual cycles are inevitably ovulatory. Currently within the general population it is unknown the proportion of regular, normal-length menstrual cycles that are ovulatory. Thus, the objective of this study was to determine the population point prevalence of ovulation in premenopausal, normally menstruating women. The null hypothesis was that such cycles are ovulatory.

Methods

This is a single-cycle, cross-sectional, population-based study—a sub-study of the HUNT3 health study in the semi-rural county (Nord Trøndelag) in mid-Norway. Participants included >3,700 spontaneously (no hormonal contraception) menstruating women, primarily Caucasian, ages 20–49.9 from that county. Participation rate was 51.9%. All reported the date previous flow started. A single, random serum progesterone level was considered ovulatory if ≥9.54 nmol/L on cycle days 14 to -3 days before usual cycle length (CL).

Results

Ovulation was assessed in 3,168 women mean age 41.7 (interquartile range, [IQR] 36.8 to 45.5), cycle length 28 days (d) (IQR 28 to 28) and body mass index (BMI) 26.3 kg/m2 (95% CI 26.1 to 26.4). Parity was 95.6%, 30% smoked, 61.3% exercised regularly and 18% were obese. 1,545 women with a serum progesterone level on cycle days 14 to -3 were presumed to be in the luteal phase. Of these, 63.3% of women had an ovulatory cycle (n = 978) and 37% (n = 567) were anovulatory. Women with/ without ovulation did not differ in age, BMI, cycle day, menarche age, cigarette use, physical activity, % obesity or self-reported health. There were minimal differences in parity (96.7% vs. 94.5%, P = 0.04) and major differences in progesterone level (24.5 vs. 3.8 nmol/L, P = 0.001).

Conclusion

Anovulation in a random population occurs in over a third of clinically normal menstrual cycles.     

Changes in women's sexual interests and their partners' mate-retention tactics across the menstrual cycle: evidence for shifting conflicts of interest

Because ancestral women could have obtained genetic benefits through extra-pair sex only near ovulation, but paid costs of extra-pair sex throughout the cycle, one might expect selection to have shaped female interest in partners, other than primary partners, to be greater near ovulation than during the luteal phase. Because men would have paid heavier costs if their partners had extra-pair sex near ovulation, one might also expect selection to have shaped males' efforts to track their primary partners' whereabouts to be increased near ovulation, relative to the luteal phase. Women filled out questionnaires about their sexual interests and their partners' mate-retention tactics twice: once within 5 days before a lutenizing hormone surge and once during the luteal phase. Results showed that: (i) women reported greater sexual interest in, and fantasy about, non-primary partners near ovulation than during the luteal phase; (ii) women did not report significantly greater sexual interest in, and fantasy about, primary partners near ovulation; (iii) women reported that their primary partners were both more attentive and more proprietary near ovulation.     

Vocal cues of ovulation in human females

Recent research has documented a variety of ovulatory cues in humans, and in many nonhuman species, the vocal channel provides cues of reproductive state. We collected two sets of vocal samples from 69 normally ovulating women: one set during the follicular (high-fertility) phase of the cycle and one set during the luteal (low-fertility) phase, with ovulation confirmed by luteinizing hormone tests. In these samples we measured fundamental frequency (pitch), formant dispersion, jitter, shimmer, harmonics-to-noise ratio and speech rate. When speaking a simple introductory sentence, women's pitch increased during high- as compared with low-fertility, and this difference was the greatest for women whose voices were recorded on the two highest fertility days within the fertile window (the 2 days just before ovulation). This pattern did not occur when the same women produced vowels. The high- versus low-fertility difference in pitch was associated with the approach of ovulation and not menstrual onset, thus representing, to our knowledge, the first research to show a specific cyclic fertility cue in the human voice. We interpret this finding as evidence of a fertility-related enhancement of femininity consistent with other research documenting attractiveness-related changes associated with ovulation.     

Pulsatile infusion of gonadotrophin releasing hormone (GnRH): investigative and therapeutic applications

Normal gonadotrophin secretion, and therefore normal ovarian function, depend on delivery to the pituitary of the hypothalamic neuropeptide gonadotrophin releasing hormone (GnRH) in a pulsatile pattern. In the mid-follicular phase of the menstrual cycle, for example, discrete pulses of luteinizing hormone (LH) can be observed at approximately 90 min intervals. Many disorders of ovulation are caused by abnormalities of this natural pulsed signal. We have developed and used a small portable infusion pump to deliver GnRH to women with hypothalamic amenorrhoea; our studies, and those of other groups, have shown that successful ovulation and pregnancy result from such treatment. The results of treatment at St Mary's Hospital show that 16 women with hypogonadotrophic amenorrhoea received a total of 31 cycles of treatment with pulsatile GnRH; 25 (81%) of these cycles were ovulatory and 11 of the 14 women who were trying to conceive became pregnant. There was only one multiple pregnancy (twins).     

Short- and long-term effects of unilateral ovariectomy in sheep: causative mechanisms

The mechanisms of ovulatory compensation following unilateral ovariectomy (ULO) are still not understood. In the present study, we investigated the short- and long-term effects of ULO in sheep using transrectal ovarian ultrasonography and hormone estimations made during the estrous cycle in which surgery was done, the estrous cycle 2 mo after surgery, and the 17-day period during the subsequent anestrus. The ULOs were done when a follicle in the first follicular wave of the cycle reached a diameter > or =5 mm, leaving at least one corpus luteum and one ovulatory-sized follicle in the remaining ovary. Ovulation rate per ewe was 50% higher in the ULO ewes compared with the control ewes at the end of the cycle during which surgery was performed, but it did not differ between groups at the end of the cycle, 2 mo later. This compensation of ovulation rate in ULO ewes was due to ovulation of follicles from the penultimate follicular wave in addition to those from the final wave of the cycle. Ovulation from multiple follicular waves appeared to be due to a prolongation of the static phase of the largest follicle of the penultimate wave of the cycle. Interestingly, the length of the static phase of waves was prolonged in ULO ewes compared with control ewes in every instance where the length of the static phase could be determined. Changes in follicular dynamics due to ULO were not associated with alterations in FSH and LH secretion. In conclusion, ovulatory compensation in ULO sheep involves ovulation from multiple follicular waves due to the lengthened static phase of ovulatory-sized follicles. These altered antral follicular dynamics do not appear to be FSH or LH dependent. Further studies are required to examine the potential role of the nervous system in the enhancement of the life span of the ovulatory-sized follicles leading to ovulatory compensation by the unpaired ovary in ULO sheep.     

Female body odour is a potential cue to ovulation

Human body odours have been reported to influence female mate choice. Women prefer the odours of immunocompatible men and, during their fertile period, judge the body odours of men with symmetrical bodies--which is indicative of genetic quality--as sexy and pleasant. The reproductive success of men largely depends on mating with fertile women, but it is not known whether men can detect a woman's fertile period. We asked women who had regular menstrual cycles and who were not using hormonal contraceptives to wear a T-shirt for three consecutive nights during their late follicular (ovulatory) phase and another T-shirt during the luteal (non-ovulatory) phase of their menstrual cycle. Male raters judged the odours of T-shirts worn during the follicular phase as more pleasant and sexy than odours from T-shirts worn during the luteal phase. The odour differences between the follicular and luteal phases did not dissipate quickly over time as male raters were able to detect and judge follicular phase body odours as more pleasant and sexy than the odours from the luteal phase even after the T-shirts were kept at room temperature for one week. These findings suggest that ovulation may not be concealed and that men could use ovulation-linked odours in their mate selection.     

Behavioral indicators of ovarian phase in white-faced capuchins (Cebus capucinus)

In many primate species, conspicuous behavioral and/or morphological changes are indicators of the fertile phase of the female cycle. However, several primate species, such as the white-faced capuchin, lack these cues. This is referred to as "concealed ovulation," and is argued to be a reproductive strategy that confuses paternity and lowers the risk of infanticide. We studied 10 adult female white-faced capuchins in Santa Rosa National Park, Costa Rica, from January to June 2002. We determined their ovarian cycling patterns by analyzing fecal ovarian hormones, and compared simultaneously collected behavioral data to determine which, if any, cues females use to signal their fertile phases. We found that four females cycled during the study period but ceased to cycle without becoming pregnant. We considered several explanations for the lack of conception during our study, including reproductive seasonality. We found that female C. capucinus showed only small increases in rates of affiliative/proceptive behaviors directed toward adult males during their periovulatory phases. The best indicator of cycle phase was a significant increase in male affiliative behaviors (e.g., following and grooming bouts) and sexual behaviors (e.g., copulations and courtship displays) directed toward females during the periovulatory phase compared to the nonovulatory phase. Our finding that females exhibit little proceptive behavior, but that copulations and male courtship are nonetheless concentrated in periovulatory phases suggests that even though females do not provide behavioral and morphological cues to ovulation, males are still able to detect it. Infanticide occurs with some frequency in these monkeys, and there is evidence for postconceptive mating as a female strategy to lower risk of infanticide via paternity confusion. However, despite this occurrence of nonconceptive mating and the absence of female cues to ovulation, truly concealed ovulation does not appear to be characteristic of this study population of white-faced capuchins.     

Non-steroidal anti-inflammatory drugs (NSAIDs) and ovulation: lessons from morphology

Ovulation constitutes the central event in ovarian physiology, and ovulatory disfunction is a relevant cause of female infertility. Non-steroidal anti-inflammatory drugs (NSAIDs), widely used due to their analgesic and anti-inflammatory properties, consistently inhibit ovulation in all mammalian species investigated so far, likely due to the inhibition of cyclooxygenase 2 (COX-2), the inducible isoform of COX, that is the rate-limiting enzyme in prostaglandin (PG) synthesis. COX-2 inhibition has major effects on ovulation, fertilization and implantation, and NSAID therapy is likely implicated in human infertility and could be an important, frequently overlooked, cause of ovulatory disfunction in women. Although there is compelling evidence for a role of PGs in ovulation, the molecular targets and the precise role of these compounds in the ovulatory process are not fully understood. Morphological studies from rats treated with indomethacin (INDO), a potent inhibitor of PG synthesis, provide evidence on the actions of NSAIDs in ovulation, as well as on the possible roles of PGs in the ovulatory process. Cycling rats treated with INDO during the preovulatory period show abnormal ovulation, due to disruption of the spatial targeting of follicle rupture at the apex. Noticeably, gonadotropin-primed immature rats (widely used as a model for the study of ovulation) show age-dependent ovulatory defects similar to those of cycling rats treated with INDO. These data suggest that NSAID treatment disrupts physiological mechanisms underlying spatial targeting of follicle rupture at the apex, which are not fully established in very young rats. We summarize herein the ovulatory defects after pharmacologic COX-2 inhibition, and discuss the possible mechanisms underlying the anti-ovulatory actions of NSAIDs.     

Is preference for ovulatory female's faces associated with men's testosterone levels?

Women's ovulation is perceivable with different senses. Already subtle face shape differences are enough to trigger men's preference for the ovulatory female. The aim of the present study is to investigate if men's testosterone level can be linked to their preference for the ovulatory female. Thirty-nine heterosexual participants were shown face pairs of which one of them was transformed to the shape of a prototype face of a woman in her luteal cycle phase and the other was transformed to the shape of a prototype face of an ovulatory woman. Participants were asked to choose the face which they perceived as being more attractive (attractiveness task), or the woman with whom they would have better chances to get a date (dating task). In both tasks, the ovulatory female was chosen more often. Testosterone was not predictive for the chosen face; regardless of testosterone level men preferred the ovulatory woman. However testosterone predicted how confident the men were with their choice. Men with lower testosterone levels were more confident with their choice than men with higher testosterone levels.     

Cycling on the fast track: Ovulatory shifts in sexual motivation as a proximate mechanism for regulating life history strategies

In an ancestral world without modern contraception, how did women regulate their fertility? We argue that fertility may be regulated by context-dependent changes in sexual motivation that are specific to the high-fertility phase of the menstrual cycle. Accordingly, we predicted that ovulatory changes in sexual motivation would vary as a function of women's life history strategies, operationalized in terms of exposure to adverse childhood environments (high unpredictability, low SES, and low father quality). We tested this prediction in a sample of 1004 naturally cycling, pair-bonded women recruited using Amazon Mechanical Turk. Data show that women from adverse childhood backgrounds experienced higher in-pair sexual motivation and engaged in more in-pair sexual behavior at high fertility, compared to women from childhood backgrounds with low adversity. Women from low-adversity childhood backgrounds were more likely to exhibit ovulatory decreases in sexual motivation at early stages in their relationships. We found little evidence, however, that childhood environments interact with conception risk to predict women's extra-pair motivation and behavior. Results offer evidence that women may possess evolved psychological and behavioral mechanisms for regulating the timing of reproduction.     

Effects of age,lactation, and repeated cycles on rhesus monkey copulatory intervals

Young, sexually mature female rhesus monkeys copulate on more days prior to conception than do older females, and this prolonged discrete mating period is associated with an earlier rise in serum estradiol prior to the first ovulation of the breeding season. The influence of repeated ovulatory cycles and the presence of a suckling infant on the copulatory patterns were examined in two separate analyses. Extending previous work, young, nulliparous females copulated on more days at the first ovulation of the breeding season than did older, multiparous females. However, the duration of the copulatory period at the second ovulation of the breeding season was similar and significantly shorter for both age groups. Furthermore, the presence of a suckling infant did not influence the duration of the mating periods in adult, multiparous females. The onset of copulatory behavior for all females was associated with serum estradiol concentrations of approximately 90 pg/ml, indicating that the age and cycle differences in the duration of the copulatory periods are due to the time course of serum estradiol prior to ovulation. A separate, longitudinal analysis of the duration of the mating period associated with the first ovulation of three successive breeding seasons indicated that females copulated on more days during their first ovulatory cycle of their first breeding season. These data indicate that the copulatory interval is longer for females during the first ovulation of the breeding season, and this pattern is accentuated in young, sexually mature animals.     

Study on the ATPasic lymphocytic activity during menstrual cycle

We previously studied ATPasic activity in the lymphocyte according to sex, age and in pregnant women. Now we considered it is interesting to go on with out study with the dosage of ATPasic lymphocytic activity during menstrual cycle, monitored with basal temperature method. The methodology we followed is Ellegaard and Dimitrov one of 1972, with modifications and simplifications while the proteins dosage in the supernatant has been effected with biuret method. Our data showed a decrease of the ATPasic lymphocytic activity at the middle of cycle for ovulatory cycles, while there is no difference between data at the middle of the cycle and in menstruation for cycle without ovulation. We suppose a connection between ATPasic lymphocytic activity and the hormones which stimulate ovulation.