The function of menstrual taboos among the dogon

Menstrual taboos are nearly ubiquitous and assume parallel forms in geographically distant populations, yet their function has baffled researchers for decades. This paper proposes that menstrual taboos are anticuckoldry tactics. By signaling menstruation, they may advertise female reproductive status to husbands, affines, and other observers. Females may therefore have difficulty in obfuscating the timing of the onset of pregnancy. This may have three consequences: (a) males are better able to assess their probabilities of paternity and to direct their parental investment toward genetic offspring; (b) adulterous pregnancies are more easily detected and penalized, enhancing sexual fidelity; and (c) males avoid marrying pregnant females by relying on menstruation as evidence of nonpregnancy. This hypothesis is tested with 29 months of field data on menstrual taboos among the Dogon of Mali. Key results include the following: (a) cuckoldry is a major Dogon concern, (b) menstrual huts advertise female reproductive status, (c) husbands impose the taboos upon their wives, (d) female defiance of the taboos is undetectable and probably rare, and (e) informants think that the taboos help husbands and patrilineages to avoid cuckoldry. Thus the anti-cuckoldry hypothesis provides helpful insight into the menstrual taboos of the Dogon and should be tested among other populations. This research was supported by The Evolution and Human Behavior Program at the University of Michigan (through Dick Alexander), the L.S.B. Leakey Foundation, and the National Science Foundation (BNS-8612291). Beverly Strassmann is a National Institutes of Health postdoctoral fellow at the Reproductive Sciences Program, University of Michigan. Her primary research interest is human evolutionary ecology, with recent emphasis on menstruation in natural fertility populations, the effect of polygyny on female fitness, and reproductive endocrinology.     

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.     

Neuroendocrine aspects of migraine in women

Migraine is a complex disabling disease influenced mainly by age and gender during the life span. Neuroendocrine events related to reproductive stages and to the menstrual cycle may cause significant change in the clinical pattern of migraine over time, as a consequence of failure in adaptation higher in women than in men. Indeed, the individual threshold of vulnerability to manifest migraine is modulated by hormonal fluctuations naturally occurring throughout the menstrual cycle and at the time of reproductive transitions. In the present short review, the role of endogenous estrogen at the level of brain circuitries which are involved in multiple cellular, neurochemical and neurophysiological processes associated with migraine will be summarized in the context of reproductive milestones. In addition, some clues to recognize hormonally sensitive women on the basis of their migraine history, i.e. onset, association with menstruation or premenstrual syndrome, course during pregnancy and menopause, will be discussed in order to expand the knowledge of reproductive endocrinology in the management of migraine in women.     

Repairing Broken Rules: Care-Seeking Narratives for Menstrual Problems in Rural Mali

Narratives play an important role in the organization of therapeutic action in rural Mali. This article provides structural and interpretive analyses of a young, French-speaking Dogon woman's accounts of her efforts to manage her menstrual bleeding and threatened infertility. Through her personal narratives she creates social arenas to recruit support, negotiate changes in her family relationships, and enhance her standing as a member of the community. Beginning with the accounts of her fear and helplessness, the narrator integrates past events into her unfolding present and achieves a meaningful resolution of her problem. Her narratives weave together encounters with family members, friends, and healers to describe a therapeutic itinerary that acquires significance as a transformative experience, [narrative, therapeutic action, medical pluralism, menstruation, Dogon, Mali]     

The transient HLA antigenic loss dependent on hormonal state of organism in a healthy woman.

In a healthy 44-year-old female blood donor with HLA phenotype HLA-A 2, A 10/B 7, BW 15 repeatedly the transient loss of HLA antigens was proved during the menstrual period and supposed ovulation. Within the interval between menstruation and ovulation the antigens could reliably be proved. The results support the view that in women hormonal effects may influence the HLA antigenic expressivity. The significance of this observation for reliable typing of HLA antigens in women is discussed.     

Predictors of fecundability and conception waits among the Dogon of Mali

Surprisingly little is known about the mechanisms that underlie variation in female fertility in humans. Data on this topic are nonetheless vital to a number of pragmatic and theoretical enterprises, including population planning, infertility treatment and prevention, and evolutionary ecology. Here we study female fertility by focusing on one component of the interbirth interval: the waiting time to conception during menstrual cycling. Our study population is a Dogon village of 460 people in Mali, West Africa. This population is pronatalist and noncontracepting. In accordance with animist beliefs, the women spend five nights sleeping at a menstrual hut during menses. By censusing the women present at the menstrual huts in the study village on each of 736 consecutive nights, we were able to monitor women's conception waits prospectively. Hormonal profiles confirm the accuracy of the data on conception waits obtained from the menstrual hut census (Strassmann [1996], Behavioral Ecology 7:304–315). Using survival analysis, we identified significant predictors of the waiting time to conception: wife's age (years), husband's age (<35, 35–49, >49 years), marital duration (years), gravidity (number of prior pregnancies), and breast-feeding status. Additional variables were not significant, including duration of postpartum amenorrhea, sex of the last child, nutritional status, economic status, polygyny, and marital status (fiancée vs. married). We fit both continuous and discrete time survival models, but the former appeared to be a better choice for these data. Am J Phys Anthropol 105:167–184, 1998. © 1998 Wiley-Liss, Inc.     

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.     

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.     

Double-blind Controlled Trial of a Micronized Preparation of Flumedroxone (Demigran) in Prophylaxis of Migraine

A double-blind cross-over trial of a micronized preparation of flumedroxone, an oral progestogen derivative, and a placebo was undertaken to determine whether this drug had prophylactic value in migraine. No benefit was found in males, or in females with no history of menstrual exacerbation of migraine. In women whose migraine was worse around the time of menstruation flumedroxone resulted in statistically fewer headaches of less severity.With the dose used in this trial (micronized flumedroxone 10 mg. t.d.s.) side-effects were frequent, the commonest being polymenorrhagia, which occurred in half the women of reproductive age.     

The evolution and physiology of male pregnancy in syngnathid fishes

The seahorses, pipefishes and seadragons (Syngnathidae) are among the few vertebrates in which pregnant males incubate developing embryos. Syngnathids are popular in studies of sexual selection, sex‐role reversal, and reproductive trade‐offs, and are now emerging as valuable comparative models for the study of the biology and evolution of reproductive complexity. These fish offer the opportunity to examine the physiology, behavioural implications, and evolutionary origins of embryo incubation, independent of the female reproductive tract and female hormonal milieu. Such studies allow us to examine flexibility in regulatory systems, by determining whether the pathways underpinning female pregnancy are also co‐opted in incubating males, or whether novel pathways have evolved in response to the common challenges imposed by incubating developing embryos and releasing live young. The Syngnathidae are also ideal for studies of the evolution of reproductive complexity, because they exhibit multiple parallel origins of complex reproductive phenotypes. Here we assay the taxonomic distribution of syngnathid parity mode, examine the selective pressures that may have led to the emergence of male pregnancy, describe the biology of syngnathid reproduction, and highlight pressing areas for future research. Experimental tests of a range of hypotheses, including many generated with genomic tools, are required to inform overarching theories about the fitness implications of pregnancy and the evolution of male pregnancy. Such information will be widely applicable to our understanding of fundamental reproductive and evolutionary processes in animals.     

The non-invasive monitoring of reproductive events in wild Vervet monkeys (Cercopithecus aethiops) using urinary pregnanediol-3α-glucuronide and its correlation with behavioural observations

The reliable detection of reproductive events in free-ranging primates is usually not feasible because of the difficulty of obtaining physiological measures in the field. Utilizing a non-invasive technique, urine was collected from wild Vervet monkeys in Amboseli National Park, Kenya. Measurement of pregnanediol-3α-glucuronide levels in urine of female Vervets, combined with behavioural observations, permitted accurate estimation of conception dates for individual females. Copulatory behaviour in Amboseli Vervets was unrelated to female hormonal cycles, and females copulated both before the initiation of ovarian function and during pregnancy. This study establishes new possibilities for integrative studies of the physiology and ecology of mammals in their natural habitats.     

Menstrual cycles continue into advanced old age in the common chimpanzee (Pan troglodytes)

A long postreproductive lifespan may distinguish women from all other female primates. A long-held consensus among reproductive scientists has been that our closest living relative, the chimpanzee (Pan troglodytes), experiences menstrual cycles until death. However, a recent study of biannual assessments of gonadotropins, but lacking observations of menstruation, concluded that menopause occurs in chimpanzees between 35 and 40 yr of age. A separate report, but on wild chimpanzees, documented fertility through the 40-44 age range in all populations studied. These contradictory reports pose questions about differences between wild and captive populations and about assessments of menopause. The present study revisits this controversy by analyzing longitudinal records of anogenital swelling and menstruation in 89 female chimpanzees aged 6 to 59 yr (n = 2386 records on cycle length), monitored for most of their adult lives at the Yerkes National Primate Research Center. Twenty of these chimpanzees were observed past 39 yr of age; all 20 displayed menstrual cycles beyond this age, as confirmed by at least two observations of menses about 35 days apart. Three of these were older than 50 yr and still displayed menstrual cycles. Only the oldest female appeared menopausal, with cycles of anogenital swelling ceasing 2 yr prior to her death at age 59. Random-effects statistical modeling reveals a slight decrease in cycle length until 20 yr of age and a slight lengthening thereafter. Mean cycle length across the lifespan is 35.4 days. Our findings, based upon actual observations of menstrual cycles, suggest that menopause in the chimpanzee is rare, occurring near the end of the lifespan.     

Menstrual Cycle Phase Does Not Predict Political Conservatism

Recent authors have reported a relationship between women''s fertility status, as indexed by menstrual cycle phase, and conservatism in moral, social and political values. We conducted a survey to test for the existence of a relationship between menstrual cycle day and conservatism.2213 women reporting regular menstrual cycles provided data about their political views. Of these women, 2208 provided information about their cycle date, 1260 provided additional evidence of reliability in self-reported cycle date, and of these, 750 also indicated an absence of hormonal disruptors such as recent hormonal contraception use, breastfeeding or pregnancy. Cycle day was used to estimate day-specific fertility rate (probability of conception); political conservatism was measured via direct self-report and via responses to the "Moral Foundations” questionnaire. We also recorded relationship status, which has been reported to interact with menstrual cycle phase in determining political preferences.We found no evidence of a relationship between estimated cyclical fertility changes and conservatism, and no evidence of an interaction between relationship status and cyclical fertility in determining political attitudes. Our findings were robust to multiple inclusion/exclusion criteria and to different methods of estimating fertility and measuring conservatism. In summary, the relationship between cycle-linked reproductive parameters and conservatism may be weaker or less reliable than previously thought.     

Menstrual cycle characterization and artificial insemination in the black mangabey (Cercocebus aterrimus)

Concentrations of immunoreactive estrone conjugates, pregnanediol-3-glucuronide, and luteinizing hormone were measured and indexed to creatinine in daily urine samples from three female black mangabeys (Cercocebus aterrimus). Daily observations of menstruation and perineal tumescence were recorded. The mean ± SEM lengths of the menstrual cycle [apparent cycle length of 26.0 ± 0.8 days determined by observation of intermenstrual intervals (n = 26); physiologic cycle length of 31.3 ± 5 days determined by urinary endocrine analysis (n = 4)], follicular phase [16.5 ± 4 days (n = 4)], and luteal phase [14.8 ± 1 day (n = 4)] were determined. The apparent cycle length is probably more accurate. Perineal tumescence began during or shortly after menstruation, increased concomitantly with increasing follicular phase conjugated estrone values, and reached maximal size in the periovulatory period. Ovulation was closely followed by a drop in conjugated estrone levels, an increase in urinary pregnanediol-3-glucuronide, and perineal detumescence. Peak concentrations of conjugated estrone and luteinizing hormone values were coincident. Pregnanediol-3-glucuronide accurately reflected luteal function in the black mangabey. Knowledge of the menstrual cycle parameters and their correlation to perineal tumescence was used to time artificial inseminations. Semen was obtained by rectal electroejaculation. Coagulum and extended semen, or trypsin-digested coagulum, were used for insemination. One insemination of trypsin-digested coagulum at the external os of the cervix resulted in a probable conception, follówed by apparent abortion after 3 weeks.     

Hemispheric Specialization Varies with EEG Brain Resting States and Phase of Menstrual Cycle

A growing body of behavioral studies has demonstrated that women’s hemispheric specialization varies as a function of their menstrual cycle, with hemispheric specialization enhanced during their menstruation period. Our recent high-density electroencephalogram (EEG) study with lateralized emotional versus neutral words extended these behavioral results by showing that hemispheric specialization in men, but not in women under birth-control, depends upon specific EEG resting brain states at stimulus arrival, suggesting that hemispheric specialization may be pre-determined at the moment of the stimulus onset. To investigate whether EEG brain resting state for hemispheric specialization could vary as a function of the menstrual phase, we tested 12 right-handed healthy women over different phases of their menstrual cycle combining high-density EEG recordings and the same lateralized lexical decision paradigm with emotional versus neutral words. Results showed the presence of specific EEG resting brain states, associated with hemispheric specialization for emotional words, at the moment of the stimulus onset during the menstruation period only. These results suggest that the pre-stimulus EEG pattern influencing hemispheric specialization is modulated by the hormonal state.     

Lactation and Menstruation in Cultural Perspective

The anthropological study of women should rest upon a sound understanding of women's reproductive heritage. Current research in reproductive physiology can contribute to this understanding, particularly with reference to the lactation period. In preindustrial societies as a rule, lactation is prolonged and intensive, while menstruation is correspondingly uncommon. This is related primarily to cultural factors that interact with the suckling frequency, but other factors may be involved. Industrialization and the propagation of western attitudes have been associated with a worldwide decline in lactation; an example from Taiwan is presented. The concept of the menstrual cycle as a liminal state is introduced, and anthropologists are urged to rethink their understanding of physiologic and symbolic womanhood . [reproductive physiology, lactation, menstruation, conception, Taiwan]     

C-reactive protein across the menstrual cycle

C-reactive protein (CRP) is a widely used, sensitive biomarker of inflammation. Studies conducted among users of exogenous hormones suggest that estrogen increases CRP, whereas progesterone decreases CRP. Examinations of CRP in normally cycling women suggest the opposite: CRP is negatively associated with endogenous estrogen and positively associated with endogenous progesterone. This work evaluates the association between menstrual cycle-related hormone changes and events (menstruation and ovulation) and CRP. Eight female subjects gave urine and blood samples from twelve days across the menstrual cycle, for a total of eleven cycles. Blood samples were assayed for CRP; urine samples for beta-follicle stimulating hormone (betaFSH), pregnanediol 3-glucuronide (PDG), and estrone glucuronide (E1G). Ovulation day was estimated using hormone levels. Presence or absence of menses was reported by subjects. Analyses were conducted with random-effects linear regression. All cycles were ovulatory; day of ovulation was identified for nine cycles. A ten-fold increase in progesterone was associated with a 23% increase in CRP (P = 0.01), a ten-fold increase in estrogen was associated with a 29% decrease in CRP (P = 0.05), and menses was associated with a 17% increase in CRP (P = 0.18); no association between ovulation or FSH and CRP was found. Hormone changes across the menstrual cycle should be controlled for in future studies of inflammation in reproductive-age women.     

Life-history theory, fertility and reproductive success in humans

According to life-history theory, any organism that maximizes fitness will face a trade-off between female fertility and offspring survivorship. This trade-off has been demonstrated in a variety of species, but explicit tests in humans have found a positive linear relationship between fitness and fertility. The failure to demonstrate a maximum beyond which additional births cease to enhance fitness is potentially at odds with the view that human fertility behaviour is currently adaptive. Here we report, to our knowledge, the first clear evidence for the predicted nonlinear relationship between female fertility and reproductive success in a human population, the Dogon of Mali, West Africa. The predicted maximum reproductive success of 4.1+/-0.3 surviving offspring was attained at a fertility of 10.5 births. Eighty-three per cent of the women achieved a lifetime fertility level (7-13 births) for which the predicted mean reproductive success was within the confidence limits (3.4 to 4.8) for reproductive success at the optimal fertility level. Child mortality, rather than fertility, was the primary determinant of fitness. Since the Dogon people are farmers, our results do not support the assumptions that: (i) contemporary foragers behave more adaptively than agriculturalists, and (ii) that adaptive fertility behaviour ceased with the Neolithic revolution some 9000 years ago. We also present a new method that avoids common biases in measures of reproductive success.     

A delay differential equation model of follicle waves in women

This article presents a mathematical model for hormonal regulation of the menstrual cycle which predicts the occurrence of follicle waves in normally cycling women. Several follicles of ovulatory size that develop sequentially during one menstrual cycle are referred to as follicle waves. The model consists of 13 nonlinear, delay differential equations with 51 parameters. Model simulations exhibit a unique stable periodic cycle and this menstrual cycle accurately approximates blood levels of ovarian and pituitary hormones found in the biological literature. Numerical experiments illustrate that the number of follicle waves corresponds to the number of rises in pituitary follicle stimulating hormone. Modifications of the model equations result in simulations which predict the possibility of two ovulations at different times during the same menstrual cycle and, hence, the occurrence of dizygotic twins via a phenomenon referred to as superfecundation. Sensitive parameters are identified and bifurcations in model behaviour with respect to parameter changes are discussed. Studying follicle waves may be helpful for improving female fertility and for understanding some aspects of female reproductive ageing.     

Signal content of red facial coloration in female mandrills (Mandrillus sphinx)

Studies of secondary sexual ornamentation and its maintenance by sexual selection tend to focus on males; however, females may also possess showy ornaments. For example, female mandrills possess facial coloration that ranges from black to bright pink. We used fortnightly photographs of 52 semi-free-ranging females aged above 3years over 19 months to evaluate whether colour conveys information concerning female competitive ability, reproductive quality, age or reproductive status. Colour was not related to female rank or quality (body mass index, age at first birth or mean inter-birth interval); however, colour did increase significantly with age and primiparous females were darker than multiparous females. Colour may therefore signal reproductive quality, as younger females are less fertile and produce smaller offspring. Colour was brighter during the follicular phase than during the luteal phase, suggesting that it may signal fertility. Colour also varied across gestation and peaked at four and eight weeks post-parturition, suggesting that it may signal approaching parturition and lactation. Future studies should examine the relationship between colour and the menstrual cycle in more detail, the hormonal basis of female colour, and determine experimentally whether mandrills of both sexes attend to differences in colour between and within females.