Premenstrual Phase Research Articles

Premenstrual asthma and leukotriene variations in the menstrual cycle

Several authors have reported an increase in leukotriene C4 in the premenstrual phase in women with severe premenstrual asthma, indicating that antileukotrienes could be used in treatment. To analyse the role of leukotrienes in premenstrual asthma. A questionnaire on respiratory symptoms and peak flow during one complete menstrual cycle was given to women of fertile age to define them as asthmatics who suffered from premenstrual asthma or not. Premenstrual asthma (PMA) was defined as a clinical or functional deterioration (≥20%) in the premenstrual phase compared with the preovulatory phase. Blood samples to measure leukotriene C4 were taken during the preovulatory and premenstrual phases. Blood samples were taken in 62 asthmatic women, 34 of whom (54.3%) presented PMA criteria, all with a premenstrual deterioration of between 20 and 40%. There was no difference in leukotriene C4 levels between the preovulatory and premenstrual phases in the women who suffered from PMA (1.50ng/mL vs. 1.31ng/mL; p=0.32) and those who did not (1.40ng/mL vs. 1.29ng/mL; p=0.62). Neither were there any differences in leukotriene levels between women with or without PMA. The results were similar for each category of asthma severity. Our data show that leukotriene C4 does not appear to be involved in the pathogenesis of premenstrual asthma, or support the use of anti-leukotrienes in the specific treatment of premenstrual asthma, at least in women with a moderate premenstrual deterioration. No differences appeared in any of the categories of asthma severity.

Ovarian morphology in premenstrual dysphoria

Ovarian cyclicity is a prerequisite for premenstrual dysphoria (PMD), as illustrated by the fact that this condition is effectively eliminated by ovariectomy or by treatment with a GnRH agonist. Despite the possibility of differences in ovarian function between women with and without PMD, no study comparing ovarian morphology in these two groups has ever been published. Fifty-two women were recruited for this study; 26 had premenstrual dysphoria, fulfilling criteria slightly modified from those of the premenstrual dysphoric disorder, and 26 were asymptomatic age-matched controls. Ovarian morphology was assessed using transvaginal 7 MHz ultrasonography on day 5 after the start of menses, and venous blood was sampled for hormone analysis on days 3 and 8, the expected day of ovulation, and day -4 of the menstrual cycle. There were no significant differences between the groups with respect to the prevalence of polycystic ovaries (PCO), the total number of follicles, the total ovarian volume or serum levels of androgen hormones. In addition, serum free testosterone levels in late premenstrual phase showed an inverse association to premenstrual symptoms of irritability and a similar inverse association trend to symptoms of depressed mood. Unexpectedly, the prevalence of ovaries with fewer than five antral or growing follicles was significantly higher in women with PMD than in controls (p=0.016). While the results do not support a role for PCO or androgen hormones in eliciting late luteal phase irritability, the possible relationship between oligofollicular ovaries and PMD deserves further study.

HUBUNGAN DERAJAT KEPRIBADIAN INTROVERT DENGAN SINDROMA PRAMENSTRUASI

Introvert people tend to have distress. Psicosomatic manifestation from distress on women can be appeared as premenstrual syndrome. The aim of this study is to know the correlation between social introversion stage and premenstrual syndrome. This study is an analitic observasional study with cross sectional approach, which was held on November 2006 on Medical Faculty UNS Solo. Samples were taken by purposive sampling with restriction on new university studentsclass 2006 Medical Faculty of UNS. The requirements are : (1) on premenstrual or menstrual phase, and (2) does not have reproduction organ disease. Subject fi lled (1) Kuesioner Riwayat Menstruasi dan Ginekologi (Gynecology and Menstrual History Questionair) to know subject’s menstrual cycle, (2) Kuesioner Skala L-MMPI (L-MMPI Scale Questionair) to state honesty in answering questions given, (3) Kuesioner Sindroma Pramenstruasi (Premenstrual Syndrome Questionair) consisted of pramenstrual syndrome’s aspects, (4) Kuesioner Skala-0 MMPI (MMPI 0-Scale Questionair) to state social introversion stage. It’s obtained 42 subjects data. Social introversion stage (SI) and premenstrual syndrome (PMS) data were then analyzed with (1) Normality test by Shapiro Wilk, and (2) Hypothetic test by Pearson correlation used SPSS 11.0 for Windows computer program.Results of this study are (1) Premenstrual subjects are bigger amount than non-premenstrual subjects (88,1% vs 11,9%), (2) there is signifi cant positive correlation between social introversion stage and premenstrual syndrome with strong correlation (r=0,551; P<0,05). The conclusion of this study is there is signifi cant positive correlation between social introversion stage and premenstrual syndrome.Keywords: Social introversion, premenstrual syndrome

The Association Between the Exacerbation of Irritable Bowel Syndrome and Menstrual Symptoms in Young Taiwanese Women

Studies of irritable bowel syndrome (IBS) have focused on the relationship between IBS and the menstrual cycle in Western societies. Specifically, an exacerbation of bowel symptoms, gas, distention, diarrhea, and constipation in the premenstrual and menstrual phases has been recognized among female IBS clients. Menstrual experience is culturally specific. Thus, the purpose of this study is to determine the prevalence rate of IBS in young Taiwanese women and to identify the most prevalent symptoms of IBS among this population. Moreover, this study explores the exacerbation of IBS during menses among young Taiwanese women. A cross-sectional survey was applied. A composite of validated questionnaires including the Modified Woods Daily Health Diary and Talley's Bowel Disease Questionnaire were administered to a stratified random sample of 971 female high school students in Taipei City, Taiwan. The results indicated that exacerbation of gastrointestinal symptoms during menstruation is present among young Taiwanese women with IBS. The IBS prevalence rate was 16.2% based on the Rome II criteria. Abdominal pain had the highest severity level, and bloating was ranked second among young Taiwanese women with IBS. These symptoms significantly increased in magnitude across time from postmenstrual to premenstrual to menses.

Attitudes Toward Menstruation, Menstrual-Related Symptoms, and Premenstrual Syndrome Among Adolescent Girls: A Rural School-Based Survey

Folk culture surrounding menstrual-related matters has considerable implications for symptom expression and treatment-seeking behavior. A cross-sectional survey of 1,295 rural adolescent girls aged 13 to 19 years was conducted between February 4 and April 16, 2009 to examine these associations. With a higher score indicating a more positive attitude toward menstruation, the mean attitude score was 3.84 (SD ± 1.62) out of a maximum of six. No significant association was observed between the severity of menstrual symptoms and attitudes. Most (63.1%) of the participants identified themselves as having premenstrual symptoms, and 61.1% viewed premenstrual symptoms as a normal part of menstrual cycle. Participants with a higher severity of symptoms in the premenstrual (OR 1.05, 95% CI 1.01–1.10) and menstrual phase (OR 1.04, 95% CI 1.01–1.07), were more likely to consult a physician for premenstrual symptoms, and having a divorced/separated parents was associated with a reduced odds of consulting a physician compared to those having parents that were married (OR 0.19, 95% CI 0.05–0.83). The findings imply the need for education to help adolescent girls manage menstrual symptoms and increase awareness of the benefit of treating them. Given that menstrual-related information was widely available from mothers, family, and social culture are potentially important in shaping good menstrual attitudes.

Inflammatory Markers: Exhaled Nitric Oxide and Carbon Monoxide During the Ovarian Cycle

Nitric oxide (NO) production and carbon monoxide (CO) production are increased in inflammatory lung diseases. Although there are some pieces of evidence for hormonal modulation by estrogen, little is known about exhaled NO and CO during the ovarian cycle. In 23 subjects, we measured exhaled NO and CO by an online analyzer. Significantly higher levels of exhaled NO were found at the midcycle compared with those in the premenstrual period or during menstruation. Higher levels of CO were after ovulation and reached a peak in the premenstrual phase. The lowest levels of CO were observed in the first days of the estrogen phase. In males, there was no significant variation in exhaled NO and CO. Exhaled NO and CO levels vary during the ovarian cycle in women, and this fact should be taken into account during serial measurements of these markers in the female population.

Hypericum perforatum for the treatment of premenstrual syndrome

Premenstrual syndrome (PMS) refers to a set of emotional and physiologic symptoms occurring during the last week of the premenstrual phase and diminishing by the end of menstruation [1]. Hypericum perforatum (St John's wort) is a traditional herbal remedy that has been found to be effective at alleviating the symptoms of mild–moderate depression in those experiencing PMS [2–4]. The aim of the present study was to investigate the efficacy of H. perforatum in the treatment of PMS. In total, 170 women with PMS (for at least 6 months) who were referred to Zeinabieh Hospital, Shiraz University of Medical Sciences, Shiraz, Iran, were included in the present prospective, randomized, double-blind, placebo-controlled study. Women with current major psychiatric disorders, recent history of serious health problems, use of psychotropic medication, concomitant treatment for PMS (e.g. vitamins and supplements), current or planned pregnancy, current lactation, lack of appropriate contraception, irregular menstrual cycles, and those using oral contraceptives were excluded from the study. The American College of Obstetrics and Gynecology standard diagnostic criteria [1] were used to define PMS. Ethics approval was provided by the Institutional Review Board and the Ethics Committee of Shiraz University of Medical Sciences, and all participants gave written informed consent. The participants were randomly divided into 2 groups: those receiving H. perforatum (2 680-μg hypericin tablets per day [n=85]) and those receiving placebo (2 cellulose tablets per day [n=85]) for 8 weeks (2 menstrual cycles). Anxiety (mood swings, anxiety, or nervous tension/irritability), hydration (breast tenderness, swelling of extremities, or weight gain), depression (depression, crying, forgetfulness, or insomnia), and craving (increased appetite, headache, or fatigue) were evaluated daily on scale of 1 (not at all) to 6 (extreme). The 28-item General Health Questionnaire was used to evaluate the psychologic status of participants, all of whom completed the questionnaire prospectively during the intervention cycles and reported any adverse effects. Statistical analyses were performed using SPSS version 15.0 (SPSS, Chicago, IL, USA). The χ or Fisher exact test was applied for comparison between frequencies. Paired and independent sample t tests were used to compare means within and between groups, respectively. All tests were 2-sided and the level of significance was set at Pb0.05. There were no significant differences in baseline characteristics between the groups (Table 1). Those receiving H. perforatum had significantly lower PMS scores compared with baseline (Pb0.001) and the control group (Pb0.001). The biggest improvements in score occurred for crying (71%) and depression (52%) in the study group. More participants from the study group than the control group dropped out because of adverse events (P=0.02), although there were no significant differences in adverse events caused by the 2 preparations. H. perforatum seems to reduce premenstrual symptoms at 8 weeks of treatment, consistent with previous studies [2–4]. In their pilot study, Stevinson and Ernst [2] observed that daily intake of H. perforatum was associated with a 51% reduction in symptom ratings—consistent with the 40% reduction in the present study. Canning et al. [3] reported thatH. perforatumwasmore effective than placebo in the treatment of PMS. By measuring levels of serum sex hormones and inflammatory cytokines, they also excluded inflammatory or hormone regulation as a possible mechanism of action [3]. Consistent with the present results, Hicks et al. [4] observed that PMS mood symptoms (anxiety and depression) improved more than did other symptoms. The present study provides further evidence that H. perforatum— which is cheap and commonly available—is a well-tolerated and effective drug for the treatment ofwomenwithmoderate–severe PMS.

Síndrome pré-menstrual e percepção de impacto no desempenho esportivo de atletas brasileiras de futsal

This study’s objective was to verify the association between Premenstrual Syndrome (PMS) and perceived impact on sport performance from Brazilian indoor soccer athletes. A total of 112 athletes were enrolled, with ages varying from 18 to 31years old, and who participated in the Brazilian Clubs Cup in 2007. The instruments used were: a self-reported sheet based on criteria from the American College of Obstetricians and Gynecologist (2000) for the diagnosis of PMS and a sport performance impact perception sheet, organized in a Likert scale with values ranging from 0 (“not affected”) to 3 (“extremely affected”). Data were analyzed using the Mann-Whitney test, Pearson’s chi-square and Poisson regression with robust variance. The prevalence of PMS was 47.32% and the perceived impact on sport performance for those with PMSwas RP 1.71 (95%CI 1.23 to 2.38). The symptoms associated with sport performance impact were depression, irritability, breast tenderness, difficulty concentrating, back pain and tiredness. The intensity with which the athletes with PMS feel their performance affected during the premenstrual phase was significant in the “lowly affected “(RP 2.1 95%CI 1.26 to 3.55) and “extremely affected” (RP 3.5 95%CI 2.23 to 5.62) categories. Athletes with 6 to 9 symptoms presented higher risk (RP 3.20 95%CI 1.53 to 6.71) than athletes with 4 to 5 symptoms (RP 2.82 95%CI 1.32 to 6.05) or with 2 to 3 symptoms (RP 2.57 95%CI 1.25 to 5.30). In conclusion, the presence of PMS, the number and the kind of symptoms all exhibited associations with the sport performance impact perceived by Brazilian indoor soccer athletes.

Premenstrual syndrome and perception of impact on sport performance from brazilian indoor soccer athletes

This study’s objective was to verify the association between Premenstrual Syndrome (PMS) and perceived impact on sport performance from Brazilian indoor soccer athletes. A total of 112 athletes were enrolled, with ages varying from 18 to 31years old, and who participated in the Brazilian Clubs Cup in 2007. The instruments used were: a self-reported sheet based on criteria from the American College of Obstetricians and Gynecologist (2000) for the diagnosis of PMS and a sport performance impact perception sheet, organized in a Likert scale with values ranging from 0 (“not affected”) to 3 (“extremely affected”). Data were analyzed using the Mann-Whitney test, Pearson’s chi-square and Poisson regression with robust variance. The prevalence of PMS was 47.32% and the perceived impact on sport performance for those with PMSwas RP 1.71 (95%CI 1.23 to 2.38). The symptoms associated with sport performance impact were depression, irritability, breast tenderness, difficulty concentrating, back pain and tiredness. The intensity with which the athletes with PMS feel their performance affected during the premenstrual phase was significant in the “lowly affected “(RP 2.1 95%CI 1.26 to 3.55) and “extremely affected” (RP 3.5 95%CI 2.23 to 5.62) categories. Athletes with 6 to 9 symptoms presented higher risk (RP 3.20 95%CI 1.53 to 6.71) than athletes with 4 to 5 symptoms (RP 2.82 95%CI 1.32 to 6.05) or with 2 to 3 symptoms (RP 2.57 95%CI 1.25 to 5.30). In conclusion, the presence of PMS, the number and the kind of symptoms all exhibited associations with the sport performance impact perceived by Brazilian indoor soccer athletes.

Affect of Premenstrual Phase and Indefinite Complaints on Ability to Perform Multitasking

Affect of Premenstrual Phase and Indefinite Complaints on Ability to Perform Multitasking

Premenstrual and menstrual symptomatology in young adult Japanese females who smoke tobacco

The present study examines the correlation between premenstrual and menstrual symptomatology and smoking status in young adult Japanese females. A cross-sectional study was conducted to assess premenstrual and menstrual symptomatology using the Moos Menstrual Distress Questionnaire (MDQ). Findings were compared between smokers and nonsmokers. The correlation between symptomatology and smoking status assessed by the Fagerström Test for Nicotine Dependency (FTND) and the Reasons for Smoking Scale (RSS), which identifies smoker's motives, was determined. Data were obtained from 785 participants, including 71 smokers, 29 quitters and 685 nonsmokers. All smokers consumed 20 or fewer cigarettes per day with the exception of one heavy smoker. Smoking status affected the cycle of menstruation, but did not affect the duration. Smokers demonstrated more severe symptomatology than nonsmokers during the menstrual and premenstrual phases. Among smokers, premenstrual symptomatology was significantly more severe than menstrual symptomatology. Five premenstrual symptom groups (pain, concentration, water retention, behavior change and negative affect) were significantly higher in smokers than in nonsmokers. Overall MDQ scores and those of three subcategories (concentration, behavior change, and negative affect) during the premenstrual phase were significantly correlated with nicotine dependency and smoking motives. Smoking motives were also correlated with the severity of autonomic reaction. Our findings suggest that young adult Japanese females with a light smoking habit have severe premenstrual symptomatology, which was correlated with nicotine dependency and smoking motives.

Rapid Cycling Associated With Menstrual Periods in an Adolescent: Electrophysiological Underpinnings for Bipolarity

Rapid Cycling Associated With Menstrual Periods in an Adolescent: Electrophysiological Underpinnings for Bipolarity

Women’s spending behaviour is menstrual-cycle sensitive

When considering why women are more prone to money pathologies than men the influence of ovarian hormones cannot be ruled out. The phases of the menstrual-cycle are known to have a range of behavioural, psychological and physical correlates. It is well documented, for example, that women are more rational and controlled post-ovulation, but experience a rise in impulsive behaviour, anxiety and irritability during the pre-menstrual (or luteal) phase. At ovulation, or peak fertility, it has been shown that women adapt their dress style to impress men – known as the ornamentation effect. However, to date the role of fluctuating ovarian hormones on female economic behaviour has been largely ignored. This article reports the findings from a survey of 443 females, aged 18–50, reporting their spending in the previous seven days and their menstrual-cycle phase, follicular, mid-cycle or luteal. Women in the luteal phase were significantly less controlled and more impulsive than women earlier in their cycle. A significant correlation was also found for over-spending, lack of control and buyers’ remorse with day of cycle. These findings suggest that the adverse impact of ovarian hormones upon self-regulation may account for impulsive and excessive economic behaviour in women.

Changes in functioning of mesolimbic incentive processing circuits during the premenstrual phase

The premenstrual phase of the menstrual cycle is associated with marked changes in normal and abnormal motivated behaviors. Animal studies suggest that such effects may result from actions of gonadal hormones on the mesolimbic dopamine (DA) system. We therefore investigated premenstrual changes in reward-related neural activity in terminal regions of the DA system in humans. Twenty-eight healthy young women underwent functional magnetic resonance imaging on 2 days during the menstrual cycle, once during the late follicular phase and once during the premenstrual phase, in counterbalanced order. Using a modified version of the monetary incentive delay task, we assessed responsiveness of the ventral striatum to reward anticipation. Our results show enhanced ventral striatal responses during the premenstrual as compared to the follicular phase. Moreover, this effect was most pronounced in women reporting more premenstrual symptoms. These findings provide support for the notion that changes in functioning of mesolimbic incentive processing circuits may underlie premenstrual changes in motivated behaviors. Notably, increases in reward-cue responsiveness have previously been associated with DA withdrawal states. Our findings therefore suggest that the sharp decline of gonadal hormone levels in the premenstrual phase may trigger a similar withdrawal-like state.

Premenstrual asthma and atopy markers

The frequency of atopy in women with premenstrual asthma (PMA) and its possible effect on the premenstrual exacerbation of asthma are unknown. To analyze the relation between atopy markers (total IgE, Phadiatop, and specific IgE) and PMA. Asthmatic women of reproductive age completed a questionnaire about respiratory symptoms and recorded peak flow during an entire menstrual cycle to be classified as asthmatic patients with or without PMA. Their asthma severity was graded according to the 2005 Global Initiative for Asthma scale. PMA was defined as a clinical or functional exacerbation (>or=20%) in the premenstrual phase compared with the preovulatory phase. Blood tests for several atopy markers were conducted for: total IgE and screening for aeroallergens (Phadiatop) and specific IgE. Blood determinations were performed in 59 asthmatic women, of whom 31 (53%) had PMA. Twenty-six patients with PMA (84%) and 12 without PMA (43%) had total IgE values greater than 100 kU/L (P=.001). Twenty-one patients with PMA (68%) and 14 without PMA (50%) tested positive for Phadiatop (P=.17). Those who were positive for Phadiatop were also tested for specific IgE. No relation was found between specific IgE and PMA; values for ryegrass (63%), olive (60%), and Dermatophagoides pteronyssinus (54%) exceeded 0.35 kU/L. PMA seems to be closely linked to total IgE levels but not to specific allergens. The atopy affects the clinical manifestations of PMA in women of reproductive age.

Gynecological Management of Premenstrual Symptoms

The vast majority of menstruating women experience uncomfortable symptoms during the premenstrual phase of their menstrual cycles. Although many women do not require specific treatment of their symptoms, approximately 20% to 50% report moderate to severe premenstrual symptoms and about 5% meet the diagnostic criteria for premenstrual dysphoric disorder, the most severe manifestation of premenstrual symptoms. While the etiology of premenstrual symptoms remains unclear, several theories have implicated sex steroids and neurotransmitters in the development and manifestation of symptoms. Further complicating the delineation of etiology is that premenstrual symptoms can be somatic, psychological, or behavioral, as well as a combination of all three. Developing successful interventions for premenstrual symptoms has thus been challenging, with interventions focused on a particular aspect of premenstrual symptomatology. Treatments for premenstrual symptoms include lifestyle changes, cognitive behavioral therapies, and pharmacologic agents including ovulation suppression regimens, antidepressant medications, and anxiolytics.

Effect of premenstrual stress on autonomic function.

Premenstrual syndrome is a psychoneuro endocrine stress related disorder. To study the effect of premenstrual stress on autonomic function. Study of autonomic function basal heart rate, basal blood pressure, systolic & diastolic response to cold stimulus was carried out in 80 Eumenorrheic females age between 18-25 yrs. during premenstrual & post menstrual phase. Subjects were divided in two groups control (n-40), premenstrual syndrome group (n-40) based on presence of symptoms. Increased autonomic nervous activity with significantly increased heart rate, blood pressure, systolic & diastolic response to cold stimulus was observed during premenstrual phase. Difference of mean of autonomic function in pre and post menstrual phase in premenstrual syndrome group was significantly higher than control. Change in physiological response in premenstrual syndrome group is because of increased sympathetic activity resulting from modulation of neurotransmitter due to hormonal fluctuation.

Estimativa da ingestão de ferro e vitamina C em adolescentes no ciclo menstrual

The vitamin C and iron ingestion level was evaluated in adolescents during the three phases of the menstrual cycle. The food intake of 30 adolescents was analyzed during the premenstrual, menstrual, and postmenstrual phases, by the registration technique, with the analysis of two registrations per individual, in each phase. The prevalence estimate was done considering six dietary registrations for each adolescent. The patterns used as reference were the Dietary Reference Intakes (DRI) - Estimated Average Requirement (EAR) from Institute of Medicine - IOM (2001), using the probability approaches and the cut - point method for the iron and vitamin C respectively, in addition to the values from the Recommended Dietary Allowances (National Research Council). The adolescents were aged 15.5 +/- 1.7; the age of the menarche was 11.8 +/- 1,1; and gynecological age 3.6 +/- 1.9. The medial consumption of iron was 10.6 mg/day and of vitamin C 77.6 mg/day. It was observed by DRIs-EAR an estimate of inadequacy for iron of 22.6% and for vitamin C of 34% and by National Research Council, 63.3% and 20%, respectively. Despite the divergence among the patterns, both results shows a nutritional risk for the studied population. The accomplishment of wider dietary studies, using DRI-EAR is suggested, favoring nutritional diagnoses with subsequent evaluation of intervention measures.

Effect of menstruation on serum CA125 levels.

CA125 levels were measured in the sera of 54 women with normal menstrual cycle and without infectious, benign and malignant gynecologic disorders. In 54 subjects studied, 13 (24%) had no significant variations in serum CA125 levels throughout the menstrual cycle. In contrast, there 41 (76%) had significant variations in serum CA125 with peak levels (51.8 +/- 6.5 U/ml, mean +/- SEM) during menstruation. The concentration reached a normal value (17.7 +/- 1.6 U/ml, mean +/- SEM) at proliferative phase, and remained low throughout the rest phases of the cycle. The mean peak level was significantly higher than that at proliferative phase (P < 0.001), where as no significant difference in mean concentration was detected between sequential phases from proliferative phase to premenstrual phase (P > 0.1). Among 41 with variable CA125 levels in the menstrual cycle, more than half of them, namely 39% of the total (21/54), had the levels of the upper limit or normal values.

Decreased blood serotonin in the premenstrual phase enhances negative mood in healthy women

The purpose of this study was to evaluate mechanisms underlying the action of selective serotonin reuptake inhibitors on the improvement of negative mood symptoms in premenstrual syndrome. We assessed relationships between serotonin (5-HT) levels in the brain (estimated from 5-HT concentrations in whole blood) and negative mood states during the premenstrual phase in 13 healthy women. Mood states were evaluated using the Profile of Mood States questionnaire. We also evaluated relationships between 5-HT and ovarian hormones (oestradiol and progesterone). A significant negative correlation was seen between 5-HT concentrations in whole blood and negative mood scores (tension–anxiety and fatigue) observed in the premenstrual phase. A significant positive correlation was observed between 5-HT and oestradiol in the premenstrual phase, but not in the follicular phase. These results suggest that healthy women with lower whole blood 5-HT concentrations in the premenstrual phase exhibit enhanced negative mood due to lower 5-HT concentrations at brain synapses, which may be caused in part by lower oestrogen concentration.