The Effect of the Menstrual Cycle on Cognitive Performance: Spatial Reasoning, Visual & Numerical Memory

The menstrual cycle has been a topic of interest in relation to behavior and cognition for many years, with historical beliefs associating it with cognitive impairment. However, recent research has challenged these beliefs and suggested potential positive effects of the menstrual cycle on cognitive performance. Despite these emerging findings, there is still a lack of consensus regarding the impact of the menstrual cycle on cognition, particularly in domains such as spatial reasoning, visual memory, and numerical memory. Hence, this study aimed to explore the relationship between the menstrual cycle and cognitive performance in these specific domains. Previous studies have reported mixed findings, with some suggesting no significant association and others indicating potential differences across the menstrual cycle. To contribute to this body of knowledge, we explored the research question of whether the menstrual cycles have a significant effect on cognition, particularly in the domains of spatial reasoning, visual and numerical memory in a regionally diverse sample of menstruating females. A total of 30 menstruating females from mixed geographical backgrounds participated in the study, and a repeated measures design was used to assess their cognitive performance in two phases of the menstrual cycle: follicular and luteal. The results of the study revealed that while spatial reasoning was not significantly related to the menstrual cycle (p = 0.256), both visual and numerical memory had significant positive associations (p < 0.001) with the luteal phase. However, since the effect sizes were very small, the importance of this relationship might be commonly overestimated. Future studies could thus entail designs with larger sample sizes, including neuro-biological measures of menstrual stages, and consequently inform competent interventions and support systems.

Characteristics of abnormal menstrual cycle and polycystic ovary syndrome in community and hospital populations

Background Polycystic ovary syndrome （PCOS） is considered to be the most common endocrine disorder in women of reproductive age.The involvement of an abnormal menstrual cycle in the etiology of PCOS remains unclear.We aimed to analyze the characteristics of abnormal menstrual cycles and their association with PCOS in community and hospital patient populations.Methods Women with PCOS identified from 2111 permanent female residents in the community of Beijing and 506 outpatients obtained from the reproductive clinic of Peking University Third Hospital were recruited for this study,comprising the PCOS community group and the PCOS hospital group, respectively.Each group was further divided into four subgroups according to the length of menstrual cycles： 〈21 days; 21-34 days; 35-60 days; and 〉60 days.Women in each group were interviewed using a questionnaire to assess factors including age, age of menarche, menstrual cycle history, related family history, and modified Ferriman-Gallwey （mF-G） score.All women received transvaginal ultrasound scan and had fasting blood samples taken for endocrine evaluation.A two-tailed P value of 〈0.05 was considered significant.Results In the community population, the prevalence of abnormal menstrual cycle was 27.19% （574/2111）.The prevalence of PCOS in the community was 6.11% （129/2111） according to Rotterdam criteria.In the community group,the most common menstrual cycle length was 35-60 days, whereas for the hospital group, it was 〉60 days.In both the community and hospital groups, the most common phenotype of PCOS was that of Oligo/amenorrhea＋PCO＋hyperandrogenism （HA） （O＋P＋H） （P=0.000）.With increasing cycle length of 35-60 days to 〉60 days, the percentages of Oligo/amenorrhea＋PCO （O＋P） and O＋P＋H were found to significantly decrease in the community group and significantly increase in the hospital group （P=0.000 for each）.In the hospital group, as the menstrual cycle length increased from 35-60 days to 〉60 days, the rate of spontaneous abortion increased significantly （P=0.000）, meanwhile the rate of poorly-secreted endometrium and abnormal endometrial hyperplasia increased significantly （P=0.000）.Conclusions The prevalence of PCOS in the Beijing community of women was 6.11%.Oligo/arnenorrhea was the most common type of abnormal menstrual cycle and may be an indicator for PCOS and endometrial lesions.Gynecologists should seek relevant medical information from women in the community to promptly diagnose PCOS and then follow up patients for potential development of subsequent complications.

Dydrogesterone treatment for menstrual-cycle regularization in abnormal uterine bleeding-ovulation dysfunction patients

BACKGROUND Dydrogesterone has shown significant efficacy in treatment of irregular menstrual cycle due to abnormal uterine bleeding-ovulation dysfunction(AUB-O),but there were few relevant studies.This observational study was designed to evaluate the effectiveness of dydrogesterone for the treatment of Chinese patients with AUB-O.AIM To evaluate the effects of dydrogesterone on menstrual-cycle(MC)regularization and metabolism in the patients with AUB-O.METHODS A prospective,non-interventional,single-arm,post-marketing observational study was conducted.Chinese women aged 16 years or above with AUB-O who had been prescribed dydrogesterone were enrolled.The patients were treated with dydrogesterone 10 mg from day 16 to day 25 of each cycle,consecutively for at least 3 cycles.The main outcome was defined as the percentage of patients whose MCs returned to normal(defined as 21 d<menstrual cycle≤35 d)after three cycles of dydrogesterone treatment.RESULTS One hundred and fourteen women with AUB-O were enrolled in the present study.Of 89 patients who completed treatment,72(80.9%)achieved a regular MC at the end of the 3rd circle.The level of androgen,including testosterone and dehydroepiandrosterone sulfate,declined significantly(P=0.01 and 0.031,respectively),whereas other hormone levels remained steady.During the treatment,44/80(55.0%)subjects in the per-protocol set had reported biphasic basal body temperature.CONCLUSION Dydrogesterone therapy was effective in achieving MC regularization for Chinese patients with AUB-O.

Lymphocytes and perforin expression in endometrium during the menstrual cycle

Obejctive To study the lymphocytes, perforin protein and mRNA expression in endometrium of different phases in the menstrual cycle and to explore the regularity and role of the lymphocytes and perforin in the reproductive system Methods Immunohistochemical and in situ hybridization techniques were employed to demonstrate the population, phenotype and mediator (perforin) of lymphocytes in the proliferative and secretory endometrium Results In different phases of the endometrium, there were very few CD 3 + typical T lymphocytes, CD 4 + helper lymphocytes and CD 8 + suppressor/cytotoxic T lymphocytes, while CD 56 + lymphocyte (also named NK like cell) were abundant CD 56 + lymphocytes were absent in postmenopausal endometrium A double immunohistochemical labelling method demonstrated the co expression of perforin protein and CD 56 antigen of cells in different phases of the endometrium Quantitative analysis of CD 56 + lymphocytes and perforin positive cells increased in number from the proliferative to the secretory endometrium ( P <0 05) In situ hybridization analysis showed that perforin mRNA positive cells formed islands in proliferative endometrial stroma, but were scattered in secretory endometrium There was difference between perforin gene expression and protein expression in the proliferative endometrium Conclusions Lymphocytes and perforin expression in the endometrium at different phases of the menstrual cycle are specific and may play an important role in the reproductive system They may exert a positive influence on embryo implantation and be involved in endometrial stroma breakdown during menstruation

Expression of nucleophosmin in glandular epithelium of non-pregnant human endometrium during the menstrual cycle

Background Nucleophosmin plays a critical role in embryonic development. This study aimed to examine the expression pattern of nucleophosmin in glandular epithelium of human endometrium during the menstrual cycle. Methods Endometrial tissues used for this study were obtained from 46 non-pregnant patients who underwent hysterectomy which had been performed to treat benign diseases. Nucleophosmin expression was assessed by in situ hybridization and immunohistochemistry. Results At the early-, mid- and late-proliferative phase, nucleophosmin mRNA was highly expressed in glandular epithelium of human endometrium. At the secretory phase, the expression of nucleophosmin mRNA was reduced in glandular epithelium in early-secretory phase, and the expression in mid- and late-secretory phases was not detected. Similarly, nucleophosmin protein was strongly expressed in endometrial glands throughout the proliferative phase, but was gradually reduced during secretory phase. Conclusion Nucleophosmin mRNA and protein are expressed in glandular epithelium of human endometrium throucIhout the menstrual cycle.

Appearance of Inflammation in Peripheral Blood during Menstrual Cycles in Women of Childbearing Age

Background:Chronic inflammation has been reported as a triggering and driving factor in the pathogenesis of various diseases and is believed to be closely associated with tumor pathogenesis.In this study,we aimed to explore the changes of the inflammatory stress-related indexes during the menstrual period.Methods:Cytokines and tumor-associated carbohydrate antigens from 76 childbearing-age women during the follicular phase,luteal phase,and menstrual period were measured.Results:The expression of inflammatory indexes,such as platelets(PLT),lymphocytes(Lym),the percentage of Lym(Lym%),neutrophils(Neu),the percantage of Neu(Neu%),neutrophil-to-lymphocyte ratio(NLR),interleukin-6(IL-6),and cancer antigen 125(CA125),reached the highest level during the menstrual period.Conclusions:Female genital organs are under inflammatory stress during menstruation,which hints that the changes of the inflammatory state of the body play an important role in the pathogenesis of diseases.

Menstrual cycle characteristics as an indicator of fertility outcomes:evidence from prospective birth cohort study in China

OBJECTIVE:To evidently assess the applicability of regulate menstrual cycle(MC)characteristics in Traditional Chinese Medicine(TCM)as an indicator for fertility.METHODS:A community-based prospective cohort study was conducted in China.Between January 2010 and December 2012,women who were willing to conceive within 2 years were enrolled in the study.Other than the MC length pattern,a well-adopted MC characteristic,menstrual blood color and clots were specifically concerned for women enrolled.All participants were followed up in 2 years by trained nurses.Pregnancy rate,fecundability odds ratio(FOR)and risk of miscarriage were assessed as fertility outcomes.RESULTS:A total of 2109 women were effectively included in this cohort for analysis.Results show that women with irregular MC length were less likely to achieve conception(FOR_(irregular)=0.59;95%CI=0.45-0.77,P<0.001).Menstrual blood in bright red color was also associated with decline in likelihood of conception(FOR=0.79;95%CI=0.63-0.98,P=0.04).Women with menstrual blood in light red were at higher risk of miscarriage(OR=2.39;95%CI=0.91-6.28,P=0.08).No significant impact was found between menstrual blood clots and fertility outcomes(FOR=1.02,95%CI=0.83-1.25,P=0.88;OR=1.2695%CI=0.77-2.07,P=0.35).CONCLUSIONS:MC characteristics can be an effective and simple indicator for women’s fertility.Increasing the knowledge of MC characteristics for women in reproductive ages would bring great benefits to their preconception health conditions.

PROGNOSIS OF PATIENTS WITH BREAST CANCER RELATED TO THE TIMING OF OPERATION DURING MENSTRUAL CYCLE

Objective: To evaluate the effect of operation timing during menstrual cycle on the prognosis of patients with breast cancer. Methods: 218 operated premenopausal patients with breast cancer had been followedup for more than 10 years. Prognostic factors related to these patients had been selected to be underwent univariate analysis and multivariate analysis by Cox regression model. Results: Univariage analysis showed that the menstrual timing of operation, as other Known prognostic factors (tumor size, node status, histological grade, TNM classification, adjuvent systemic therapy, etc), had an influence on the patients' outcome. Multivariate analysis by Cox regression model indicated that diseasefree rate and overall survival rate of patients operated during the periovulatory phase (123 cases) were significantly superior to those operated during the premenstrual phase (95 cases) (P<0.01). There were no significant differences in prognosis between patients who received operations during the follicular phase (96 cases) and those during the luteal phase (122 cases) (P>0.01). Conclusion: Probably there is an optimal timing of operation for premenopausal breast cancer patients. Any prospective, randomized clinical study should be carried out to make this problem clear.

Symptomatology of irritable bowel syndrome and inflammatory bowel disease during the menstrual cycle

Gender-related physiological variations in gastrointestinal(GI)symptomatology have been observed in women of reproductive age.Many women experience cyclical changes in GI symptomatology during their menstrual cycle,particularly alteration in their bowel habits.Physiological studies of healthy women during the menstrual cycle showed a prolonged GI transit time during the luteal phase,either in the oro-cecumroute or in the colon.Worsened GI symptoms,such as abdominal pain,bloating or diarrhea are observed in patients with irritable bowel syndrome(IBS)during menses.This may be due to elevated prostaglandin levels during menses,with an enhanced perception of viscera-somatic stimuli resulting in nausea,abdominal distension and pain.Also patients with IBS or IBD demonstrate a cyclical pattern more closely related to their bowel habits than healthy controls.Women with inflammatory bowel disease(IBD)also have exacerbated symptoms during menses;however,it is unclear whether this relates to physiological variation or disease exacerbation in IBS or IBD.Studies examining the association of the menstrual cycle and GI symptomatology in patients with IBS or IBD,have not yet clarified the underlying mechanisms.Moreover medications—such as non-steroidal anti-inflammatory drugs and oral contraceptive pills used for dysmenorrhea and menstrual migraine in those patients have not well been controlled for in the previous studies,which can contribute to further bias.Understanding changes in GI symptomatology during the menstrual cycle may help to determine the true extent of disease exacerbation and proper management strategy.

Assessment of the Endothelial Function with Changed Volume of Brachial Artery by Menstrual Cycle

The endothelial function has been proven to be an important factor in the pathogenesis of atheroscle-rosis, hypertension and heart failure. The flow-mediated vasodilation (FMD) of the peripheral artery is an endothelium-dependent function. Brachial-artery ultrasound scanning is the popular method for evaluat-ing FMD.

Usefulness of Newly Devised Clomiphene Citrate Administration Method Compared with the Conventional Method in Ovulation and Pregnancy

Objective: Since not all women wish to conceive a child through aggressive treatment, we investigated the usefulness of modified repeated intracyclic clomiphene citrate (CC) therapy (repeated CC therapy) as a newly devised administration method. Methods: We evaluated the effects of CC administration on menstrual cycle length and retrospectively compared ovulation and pregnancy in 220 women who received CC at our hospital. Patients in the conventional method group received 50 mg per day for five days, starting on the fifth day of menstruation (withdrawal bleeding). Groups with and without menstrual cycle shortening after conventional CC administration were compared. The repeated CC therapy group was also compared with the non-shortened group. Repeated CC therapy was administered for the first five days as in the conventional method, and a second five-day repeat treatment was administered after an interval of five to seven days. Pregnancy rates, including indirect pregnancies, were evaluated by three different methods. Results: Ovulation and pregnancy rates were significantly better in the shortened group than in the non-shortened group (P < 0.001 and P = 0.010, respectively). Even in the non-shortened group, ovulation and pregnancy rates including indirect pregnancies were significantly improved when ovulation was observed with repeated CC therapy (P < 0.001 and P = 0.022, respectively). Conclusions: For patients whose menstrual cycle was not improved or shortened, repeated CC therapy as the newly devised CC administration method is useful as the next step after the conventional CC administration method.

月经周期中免疫球蛋白G N-糖基化的周期性变化

Immunoglobulin G(IgG)is the most abundant plasma glycoprotein and a prominent humoral immune mediator.Glycan composition affects the affinity of IgG to ligands and consequent immune responses.The modification of IgG N-glycosylation is considered to be one of the various mechanisms by which sex hormones modulate the immune system.Although the menstrual cycle is the central sex hormonerelated physiological process in most women of reproductive age,IgG N-glycosylation dynamics during the menstrual cycle have not yet been investigated.To fill this gap,we profiled the plasma IgG Nglycans of 70 healthy premenopausal women at 12 time points during their menstrual cycles(every 7 days for 3 months)using hydrophilic interaction ultra-performance liquid chromatography(HILIC-UPLC).We observed cyclic periodic changes in the N-glycosylation of IgG in association with the menstrual cycle phase and sex hormone concentration in plasma.On the integrated cohort level,the modeled average menstrual cycle effect on the abundance of IgG N-glycosylation traits was low for each trait,with the highest being 1.1%for agalactosylated N-glycans.However,intrapersonal changes were relatively high in some cases;for example,the largest difference between the minimum and maximum values during the menstrual cycle was up to 21%for sialylated N-glycans.Across all measurements,the menstrual cycle phase could explain up to 0.72%of the variation in the abundance of a single IgG glycosylation trait of monogalactosylation.In contrast,up to 99%of the variation in the abundance of digalactosylation could be attributed to interpersonal differences in IgG N-glycosylation.In conclusion,the average extent of changes in the IgG N-glycopattern that occur during the menstrual cycle is small;thus,the IgG N-glycoprofiling of women in large sample-size studies can be performed regardless of menstrual cycle phase.

Myo-inositol versus metformin effects on clinical features, endocrine and metabolic profiles in infertile women with polycystic ovary syndrome: A randomized controlled trial

Objective:To compare the effectiveness of inositol and metformin on the clinical characteristics,and endocrine and metabolic profiles of infertile polycystic ovarian syndrome(PCOS)women from Vietnam.Methods:From June 2018 to August 2022,a randomized trial was undertaken at the Hue Center for Endocrinology and Reproduction on infertile women aged 18 to 40 years with polycystic ovarian syndrome.The clinical,endocrine,and metabolic features of these individuals were assessed before and after 3 months of treatment with 2 g of inositol or 1700 mg of metformin per day.Natural pregnancy rates,adverse effects,and tolerance of inositol were recorded.Results:The study included 171 infertile PCOS women who were eligible to participate and took part in the baseline assessment,of whom 132 women participated in data analysis after 3 months.After metformin treatment,42.1%of women with oligomenorrhea experienced regular menstruation.Metformin significantly lowered body mass index(BMI),waist circumference and testosterone levels,but had no effect on other clinical characteristics,endocrine profiles,or metabolic profiles.29.2%Of women reported experiencing side effects.21%Of them attained pregnancy,which resulted in 17.1%of live births.In the inositol group,the rate of regular cycle increased by 18.2%and the total testosterone concentration significantly decreased.In overweight/obese women with PCOS,inositol significantly decreased weight,BMI,waist and hip circumferences(P<0.05).100%Of women tolerated inositol and continued treatment.18.9%Of them became pregnant,leading to 17%of live births.Conclusions:Metformin and inositol can improve weight and waist circumference in overweight/obese infertile women with PCOS.Metformin is associated with a higher rate of regular menstruation,whereas inositol is associated with a lower rate of adverse effects.The spontaneous conception,clinical pregnancy,and live birth rates between two groups are comparable.

Gallbladder endometriosis as a cause of occult bleeding

A 17-year-old girl with colicky abdominal pain andchronic anemia presented to the gastrointestinal serviceof the University Hospital of Essen. In the routineworkup, there were no pathological findings despitethe anemia. Because of the fluctuation of symptomswith a climax at the time of menstruation, consecutiveultrasound studies were performed revealing a visiblemass inside the gallbladder. This finding was confirmedby a magnetic resonance imaging (MRI) study performedat the same time. Because of the severe anemia by thattime, a cholecystectomy was performed, and histologyreconfirmed the diagnosis of isolated gallbladderendometriosis. The patient recovered well and has hadno recurrence of the disease to date.

Similarity between Spatial-temporal Expression Patterning of HOXAll and Progesterone Receptor in Human Endometrium

Objective To study HOXAll expression and its correlation with that of the progesterone receptor (PR) gene in human endometriumMethods In situ hybridization and semi-quantitative RT-PCR were used. Results HOXAll mRNA was detected in both stromal and glandular cells of normal endometrium by in situ hybridization. But the expression levels in the glandular cells had a dramatic decline or even disappearance at mid-secretory stage. Semi-quantitative RT-PCR analysis, however, demonstrated that the total expression levels of HOXAll mRNA were markedly increased in the mid-secretory endometrium, which suggested that there was an increased expression in stromal cells. Similar results were obtained for PR gene expression in human endometrium by in situ hybridization and semi-quantitative RT-PCR analysis.Conclusion HOXAll gene spatial and temporal expression patterns were similar to that of PR gene in endometrium across menstrual cycle, and HOXAll was closely related to the endometrial proliferation and differentiation during menstrual cycle, especially the establishment of receptive status in implantation.

The Association between Self-Monitored Reproductive Parameters, Pregnancy Outcomes and Acupuncture Treatment

Many women track their daily basal body temperature (BBT), an important factor in reproductive status, as a part of fertility self-management. This study involved 135 patients who had undergone conventional infertility treatment;they had weekly acupuncture treatment and we assessed BBT, menstrual cycle, menstrual period and menstrual bleeding amount pre- and post-treatment. We also analyzed the rate of insufficient description of reproductive parameters, comparing patients who had delivered a baby with those who had a miscarriage and those who did not become pregnant. Menstrual cycle and period did not show notable changes pre- and post-acupuncture treatment in all groups. Menstrual bleeding amount decreased in the no-pregnancy group. There was a suggestion that acupuncture decreased very long menstrual cycle (e.g. bimonthly) to monthly. The insufficient description rate of menstrual bleeding amount was high in all groups. Weekly discussion about monitoring reproductive parameters could improve patients’ awareness in self-management. To prevent miscarriage patients needed psychological and medical advice for careful self-management in pregnancy and menstrual cycle.

The Expression of Cyclooxygenase-2 in Cervical Cancers and Hela Cells Was Regulated by Estrogen/Progestogen

To investigate the relationship between the expression of cyclooxygenase-2 （COX-2） and menstrual cycle, the regulatory effects of 17-β-estradiol （E2） and medroxyprogesterone acetate （MPA） on the expression of COX-2 in cervical cancer Hela cells were examined. Cervical cancer specimens were obtained from 47 pre-menopausal patients. The phase of menstrual cycle was determined by case history and HE staining of uterine endometrium. COX-2 was immunohistochemically stained by SABC staining and the staining intensity was determined with computerized image analysis system. Hela cells were incubated with alcohol, E2, E2＋MPA, MPA for 12, 24 and 48 h respectively. The expression of COX-2 in Hela cells was detected by Western blotting and reverse transcriptase-polymerase chain reaction （RT-PCR）. Our results showed that the expression of COX-2 was significantly higher during proliferative phase than secretory phase （P〈0.05）, but there was no difference in the positive rate between proliferative phase and secretory phase （P〉0.05）. Incubation with E2 could significantly enhance the expression of COX-2 continually. On the contrary, E2＋MPA and MPA alone could decrease the expression of COX-2 as compared with the control and E2 group （P〈0.05 and P〈0.01 respectively）. It is concluded that the expression of COX-2 in cervical cancer of pre-menopausal patients and Hela cells was regulated by estrogen/progestogen.

CYCLIC CHANGES OF LACTATE DEHYDROGENASE IN CERVICAL MUCUS

Lactote dehydrogenase (LDH) in cervicai mucus of thirteen ovulatory women was serially determined and serum LH, FSH, E2, P and cervical mucus score were measured. There was a cyclic change in LDH activity, being high in follicular phase and luteal phase, but increasing significantly in periovulatory phase. In follicular phase, there was a negative correlation between LDH activity and E2 (r=-0. 76, P< 0. 03 ). in luteal phase, there was a positive correlation between LDH activity and P (r=0. 92, P<0. 001). The results suggest that LDH activity in cervical mucus measurment can be used as an index of predicting ovulation.

Comparison between Fast Fourier Transform and Autoregressive Model on Analysis of Autonomic Nervous Function after Food Intake in Women

Purpose: Heart rate variability (HRV) is acknowledged as a useful tool to estimate autonomic function. Fast Fourier transform (FFT) and autoregressive model (AR) are used for power spectral analysis of HRV. However, there is little evidence of agreement between FFT and AR in relation to HRV following food intake in females. In the present study, we applied both FFT and AR after food intake during the follicular and luteal phases, and compared raw low-frequency (LF) and high- frequency (HF) powers, and LF/HF ratio obtained with the two power-spectral analytical methods. Methods: All subjects participated in two sessions: follicular phase session and luteal phase session. In each session, R-R intervals were continuously recorded before and after meals, and power spectral analysis of heart rate variability was performed. We analyzed low-frequency power (LF: 0.04 - 0.15 Hz) and high-frequency power (HF: 0.15 - 0.40 Hz) by using FFT and AR. LF and HF power were computed for each 30 sec, 1 min, 2.5 min, and 5 min of the 5-min R-R data before meal intake and at 20, 40, 60 and 80 min after meal intake. The LF/HF ratio was calculated as an index of sympathovagal balance. Results: In the present study, after 30 sec and 1 min of segment analysis, there was little interchangeability between AR and FFT in LF, HF, and LF/HF ratio in both follicular and luteal phases. In 2.5 min or 5 min of segment analysis, there was interchangeability between FFT and AR in LF and HF, but not in the LF/HF ratio in both follicular and luteal phases. Additionally, FFT underestimated HRV compared with AR, and the extent of underestimation increased with increasing AR value. Conclusion: FFT underestimated HRV compared with AR, and FFT correlated poorly with AR when the analysis segment was shortened.

Electrical Activities and Pressure Pain Threshold in Oral Contraceptives Users and Nonusers

The aim is to evaluate the influence of oral contraceptive intake and menstrual cycle on the electrical activity and pressure pain threshold from anterior temporal and masseter muscles. Twenty-eight women on reproductive age were selected, 13 OC users and 15 nonusers. They were weekly submitted to electromyography and algometry of the anterior temporal and masseter muscles during three consecutive menstrual cycles. Electrical activities at rest position and PPTs of temporal and masseter muscles were not affected by menstrual cycle or by OCs uses. Comparison between groups demonstrated that working side electrical activity was increased in OC users in both muscles, except during lutheal phase for the anterior temporal. However, comparison within weeks did not demonstrate statistical difference. It was suggested that, in healthy women, oral contraceptive use may influence electrical activity, but different phases of the cycle may not.