Effects of menstrual cycle on background parenchymal enhancement and detectability of breast cancer on dynamic contrast-enhanced breast MRI: A multicenter study of an Asian population.

PURPOSE: To evaluate the effect of the menstrual cycle on BPE and cancer detectability in an Asian population. MATERIAL AND METHODS: 266 premenopausal patients with regular menstrual cycles from 24 centers were included, and 176 of them were diagnosed by pathology as having breast cancer. Thirty-five patients were examined in the menstrual phase (days 1-4), 105 in the proliferative phase (days 5-14), and 126 in the secretory phase (days 15-30). Measurement of the following signal intensities (SIs) were obtained: breast tissue on the unaffected side on a pre-contrast image (SI1) and an early-phase image (SI2); the SIs of breast tissue on the affected side on a pre-contrast image (SI3) and an early-phase image (SI4); and the SIs of breast cancer on a pre-contrast image (SI5) and an early-phase image (SI6). We calculated the BPE ratio, i.e., (SI2- SI1)/SI1 and the cancer/background enhancement ratio (C/B) ratio, i.e., (SI6- SI5) / (SI4- SI3). The BPE was classified as minimal, mild, moderate, or marked, and the cancer detectability was classified as excellent, good, or poor independently by two radiologists. RESULTS: The average C/B ratio was 20.1, 15.7, and 9.1 at the menstrual, proliferative, and secretory phases (p < 0.001). BPE was determined as moderate or marked in 0% and 5.4% at the menstrual phase, 10.3% and 11.0% at the proliferative phase, and 17.5% and 21.7% at the secretory phase by the two observers, respectively (p = 0.01, p = 0.01). The detectability of breast cancer was classified as poor in 0% and 0%, 1.4% and 13.0%, and 8.0% and 22.1% at the menstrual, proliferative, and secretory phases by the two observers, respectively (p = 0.07, p = 0.02). CONCLUSION: The menstrual phase and the proliferative phase seem to be suitable for breast MRI of Asian women.

Menstrual Cycle Hormone Changes in Women Traversing Menopause: Study of Women's Health Across the Nation.

Context: Menstrual cycle hormone patterns in women approaching menopause are inadequately studied. Objective: To describe day-to-day menstrual cycle hormones in women as they approach menopause from the Study of Women's Health Across the Nation Daily Hormone Study (DHS). Design: DHS enrollees collected daily urine for one entire menstrual cycle or up to 50 days, whichever came first, annually, up to the final menstrual period (FMP) or for up to 10 years. Setting: Seven sites across the United States. Participants: A total of 511 premenopausal or early perimenopausal women at enrollment, within 10 years before menopause. Intervention: Time-to-FMP measurement. Main Outcome Measures: Evidence of luteal activity (ELA), determined using objective algorithms. Menstrual cycle/segment length; whole cycle, and segment integrated urinary luteinizing hormone, follicle-stimulating hormone, estrone conjugates, and pregnanediol glucuronide (Pdg) for each year, organized around the FMP. Results: Mean menstrual cycle length was remarkably preserved at 26 to 27 days in ELA cycles; non-ELA cycles had greater variability. The percentage of cycles that were ELA remained high until 5 years before the FMP (87.9%); only 22.8% of cycles within 1 year of the FMP were ELA. Whole cycle hormones remained relatively stable up to 3 years before the FMP, when gonadotropins began to increase. Pdg excretion declined slowly with progress to the FMP, but Pdg patterns of ELA cycles remained distinguishable from non-ELA. Conclusions: Menstrual cycle hormone patterns in perimenopausal women resemble those of midreproductive-aged women until 5 years before menopause, and presumably ovulatory cycles retain a potentially fertile pattern up to the end of reproductive life.

Circulating androgens and SHBG during the normal menstrual cycle in two ethnic populations.

The objective of this study was to study possible ethnic differences in steroid hormones and sex hormone-binding globulin (SHBG) during the menstrual cycle. Serum levels of the ovarian steroids estradiol (E2) and progesterone (P) and of follicle-stimulating hormone (FSH), luteinizing hormone (LH), SHBG, dehydroepiandrosterone (DHEA) and testosterone (T-ria) were all measured by immunoassay during the menstrual cycle in 15 Swedish and 11 West Asian regularly menstruating women. Testosterone (T-ms) was also measured by LC-MS/MS and so were 4-androstene-3,17-dione (A-4) and 17-alpha-hydroxyprogesterone (17-OHP). There were no ethnic differences in levels of ovarian steroids, gonadotrophins, A-4, 17-OHP and T-ms. DHEA were significantly higher and SHBG significantly lower in West Asian than in Swedish women. Surprisingly, T-ria was significantly higher in West Asian than in Swedish women and higher than T-ms (47% in Swedish and 107% in West Asian women). The difference (T-ria - T-ms) showed strong positive correlations to DHEA in the total and in West Asian but not in Swedish women, indicating an influence of DHEA/DHEAS metabolites on the T-ria results. In conclusion, ethnic differences in cross reacting steroids may cause erroneous results in one ethnic group by a steroid immunoassay having reasonable specificity in another. The reasons for the lower SHBG and the higher DHEA levels in West Asian women are not known. The results raise the question about establishing different reference values for certain analytes in different ethnic groups.

Efficacy of combined hormonal vaginal ring in comparison to combined hormonal pills in heavy menstrual bleeding.

OBJECTIVE: To compare the efficacy, acceptability and compliance of combined hormonal vaginal ring (CVR), with combined hormonal pills (CHP) in patients with heavy menstrual bleeding (HMB). STUDY DESIGN: This prospective study was conducted in 50 women with HMB in age group of 25-40 years. Patients were divided in two groups of 25 each and followed for six treatment cycles. In each group, cycle comprised of three weeks of CVR (releases 15µg of EE and 120µg of the etonogestrel per day) or CHP (containing 30µgm of EE and 150µgm of LNG) use, followed by one ring or pill free week. After each cycle, patients were evaluated about the amount of blood loss and duration of bleeding by the pictoral blood assessment chart (PBAC), early bleeding (EWB), continued bleeding (CWB), intermenstrual bleeding, intended bleeding, compliance, and user acceptability. The collected data were analyzed using the Chi square test, t-test and ANOVA test. RESULT: Reduction in PBAC score for CVR (70.73%) and CHP group (70.02%), duration of bleeding and incidence of EWB was comparable among the two groups. The incidence of intermenstrual bleeding was lower in CVR than in CHP group in cycle 3 and 4 with significant p value. The incidence of CWB was significantly lower and the incidence of intended bleeding pattern in CVR group was significantly higher in cycle 3, 4, 5 and 6, signifying better cycle control. Compliance was also higher in CVR (88%) than CHC (75.33% of all cycles). CONCLUSION: This trial suggests that both the CVR and CHP are very effective short-term treatments for HMB in reproductive age group. However, women had better cycle control and compliance with CVR. This may be an attractive option among the wide variety of medications used to treat HMB.

Novel correlates between antimüllerian hormone and menstrual cycle characteristics in African-American women (23-35 years-old).

OBJECTIVE: To characterize normative antimüllerian hormone (AMH) levels and ascertain which factors are associated with AMH in a large cohort of reproductive-age women. DESIGN: Cross-sectional study. SETTING: Not applicable. PATIENT(S): A total of 1,654 African-American women (AAW) ages 23-34 at recruitment. INTERVENTION(S): Not applicable. MAIN OUTCOME MEASURE(S): Serum AMH measured using an ultrasensitive ELISA. RESULT(S): The median AMH was 3.18 ng/mL, and there was a significant, but nonlinear, relationship between age and AMH, with levels peaking at age 25. As AMH was not normally distributed, log transformation was performed and used for all analyses. In a multivariable age-adjusted model, body mass index, current use of hormonal contraception, and history of a thyroid condition were inversely associated with AMH, while history of abnormal menstrual bleeding and menstrual cycles longer than 35 days were positively associated with AMH. CONCLUSION(S): While age is correlated with AMH, it accounts for only a portion of the variation seen. This study adds valuable information to the existing literature on normative AMH levels in young reproductive-age women. While our findings fill a critical data gap for ovarian reserve in AAW, the insights gained will be of benefit for all women.

Increasing serum 25-hydroxyvitamin D is associated with reduced odds of long menstrual cycles in a cross-sectional study of African American women.

OBJECTIVE: To examine the association between serum 25-hydroxyvitamin D [25(OH)D] and menstrual cycle length and regularity. DESIGN: Community-based, cross-sectional study of serum 25(OH)D (adjusted for seasonal differences in timing of blood draw) and menstrual cycle length. Women aged 23-34 years reported their gynecologic history. Menstrual cycles were described with four independent categories (normal, short, long, irregular). We used polytomous logistic regression to estimate the association between a doubling of seasonally adjusted 25(OH)D and the odds of each cycle category. SETTING: Not applicable. PATIENT(S): A total of 1,102 African American women. INTERVENTION(S): Not applicable. MAIN OUTCOME MEASURE(S): Self-reported menstrual cycle length over the previous 12 months, excluding women who were using cycle-regulating medications over the entire year. Women who reported that their cycles were "too irregular to estimate" were classified as having irregular cycles. A typical cycle length of <27 days was considered "short," >34 days was "long," and 27-34 days was "normal." RESULT(S): The median 25(OH)D level was 14.7 ng/mL (interquartile range, 10.9-19.6 ng/mL). A doubling of 25(OH)D was associated with half the odds of having long menstrual cycles: adjusted odds ratio (aOR) 0.54, 95% confidence interval (CI) 0.32-0.89. 25-Hydroxyvitamin D was not associated with the occurrence of short (aOR 1.03, 95% CI 0.82-1.29) or irregular (aOR 1.46, 95% CI 0.88-2.41) menstrual cycles. Results were robust to several sensitivity analyses. CONCLUSION(S): These findings suggest that vitamin D status may influence the menstrual cycle and play a role in ovarian function. Further investigation of 25(OH)D and ovarian hormones, and prospective studies of 25(OH)D and cycle length, are needed.

Influence of race/ethnicity, body mass index, and proximity of menopause on menstrual cycle patterns in the menopausal transition: the Study of Women's Health Across the Nation.

OBJECTIVE: Few studies have evaluated factors that influence menstrual cycle length (MCL) during the menopausal transition (MT), a life stage during which very long cycles become more likely to occur. The objective of this article was to assess how body mass index and race/ethnicity--factors associated with MCL in young women--influence MCL during the MT. METHODS: Study of Women's Health Across the Nation menstrual calendar substudy data of African-American, white, Chinese, and Japanese women were available for three sites (southeastern Michigan, Los Angeles, and northern California). Self-recorded monthly menstrual calendars with end-of-the-month questions on hormone therapy use and smoking were collected from 1996 to 2006. Height and weight were measured at annual study visits. We used quantile regression to model MCL at the 25th, 50th, 75th, and 90th percentiles with bootstrap sampling to construct 95% CIs. Models evaluated MCL with time indexed to the start of the MT (n = 963) and to the final menstrual period (n = 431). RESULTS: During the MT, increases in MCL occurred mostly at the right tail of the distribution, reflecting a lengthening of long menstrual cycles, not of the median MCL. After adjustment for smoking, education, physical activity, and time, Chinese and Japanese women had 1 day to 6 days longer MCLs compared with white women. Obese women had 1 day to 5 days longer MCLs compared with nonobese women. CONCLUSIONS: As occurs in younger women, menstrual characteristics during the MT are influenced by race/ethnicity and obesity. The long menstrual cycles characteristic of the MT are longer in obese women and in Chinese and Japanese women.

In the secretory endometria of women, luminal epithelia exhibit gene and protein expressions that differ from those of glandular epithelia.

OBJECTIVE: To characterize the transcriptome of luminal epithelia (LE) of fertile secretory endometria and compare the results with those from glandular epithelia (GE). DESIGN: Endometrial samples were collected at 2 and 7 days after initial blood LH surge in separate menstrual cycles. LE were obtained with the use of laser microdissection. mRNA was amplified with the use of linear polymerase chain reaction and hybridized to Agilent 4×44 microarrays. Gene analysis was used to identify differentially expressed mRNAs. Immunohistochemistry was used to assess nine proteins. SETTING: One IVF clinic. PATIENT(S): Seven Caucasian fertile cycling women. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Cycle dating with the use of blood endocrinologic markers, microarrays of laser-microdissected LE, immunohistochemical analysis. RESULT(S): One hundred sixty-one (of 401) differentially expressed mRNAs in LE were identified from the metabolism pathway. Increased selective protein expression in LE at 7 days after initial LH surge was observed. LE mRNA expression was the converse of that in GE. The two cell types each had a different significant biologic pathway identified. CONCLUSION(S): Our results introduce a new concept that LE differentially expressed mRNAs are in the converse direction to that of GE, indicating different biologic processes despite the GE being continuous with the luminal monolayer. This probable distinction of biologic roles has not been noted previously. Further investigations must take cognizance of this observation.

Race/ethnic disparities in reproductive age: an examination of ovarian reserve estimates across four race/ethnic groups of healthy, regularly cycling women.

OBJECTIVE: To determine whether reproductive age, as indexed by a validated marker of ovarian reserve (antimüllerian hormone [AMH]), varies among women of different race/ethnic backgrounds. DESIGN: Cross-sectional study. SETTING: Community-based sample. PATIENT(S): Multiethnic sample of 947 (277 white, 237 African American, 220 Latina, and 213 Chinese) healthy and regularly cycling premenopausal women, ages 25-45. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): AMH level. RESULT(S): A multivariate model was fit examining race/ethnicity, covariates, nonlinear terms for age (age(2), age(3)), and body mass index (BMI(2), BMI(3)), and two-way interactions between race/ethnicity and each of the other predictor variables in relation to AMH. After backward elimination, significant effects included race/ethnicity (F = 8.45), age (F = 349.94), race/ethnicity-by-linear age interaction (F = 4.67), age(2) (F = 31.61), and BMI (F = 10.69). Inspection of the significant race/ethnicity-by-linear age interaction showed AMH levels were consistently lower among Latina women compared with white women across all ages, whereas AMH levels were lower among African American and Chinese women compared with the white women at younger and middle ages, respectively. The AMH levels were higher among African American compared with Latina and Chinese women at older ages. CONCLUSION(S): Although the results must be considered preliminary, the findings are twofold: African American women may have lower AMH levels at younger ages but experience less of a reduction in AMH with advancing age, and Latina and Chinese women compared with white women may have lower AMH levels, marking a lower ovarian reserve and a possibly increased risk for earlier menopause.

Predicting the timeline to the final menstrual period: the study of women's health across the nation.

CONTEXT: Predicting the final menstrual period (FMP) would help women know when their menopause transition will be completed. Additionally, biological changes, such as accelerated bone loss, precede the FMP by at least 1 year. OBJECTIVE: Our objective was to assess whether FSH, estradiol, or urinary N-telopeptide predict where an individual is on her timeline to FMP. METHODS: The sample was 554 women from the Study of Women's Health Across the Nation. We modeled the probability of having crossed specified landmarks: 2 years before, 1 year before, and the FMP. We also modeled the probability of being in narrower intervals: 2 to1 year before FMP, 2 years before FMP and FMP, or 1 year before FMP and FMP. We determined the candidate markers that best predicted having crossed each landmark, with the optimum defined as the greatest area under the receiver-operator curve; created formulas for the probability of having crossed each landmark; and calculated sensitivity and specificity. RESULTS: Final models included current estradiol and FSH (each as a fraction of 1 previous reference measure), age, menopause transition stage, race/ethnicity, and whether serum was collected during the early follicular phase. Areas under the receiver-operator curves of final models that predicted the probability of a woman having crossed 2 years before, 1 year before, and the FMP itself were 0.902, 0.926, and 0.945, respectively. If we classified women as having crossed the 2 years before the FMP landmark when predicted probability exceeded 0.3, sensitivity was 85% and specificity 77%. CONCLUSION: This model could help patients and researchers estimate the time to FMP.

Edad de menarquia y ascendencia indígena: Un estudio poblacional en Chile / Age at menarche and indigenous ancestry: A population study in Chile

Background: The age at menarche may influence decisively health and disease in women. It also indicates the beginning of the reproductive period and, as a consequence, the possibility of biological continuity for the human species. Genetic and environmental determinants define the age of menarche and can explain differences found among different populations. Aim: To determine the age at menarche among adolescents with different levels of indigenous descent (parental indigenous surnames), considering the effect of socioeconomic and demographic factors. Material and Methods: An observational study of historic cohorts of8.624 girls from the Arauca-nía Region (central-southern Chile) was carried out. Data were collected by health professionals using a previously validated questionnaire. Occurrence of menarche was estimated through survival analysis and compared between groups (according to indigenous parental surnames) adjusted for parents' income and educational level and provenance (rural/urban). Results: Estimated median age of menarche was 151 months (95% Cl: 150-151). In female with four indigenous surnames, menarche occurred two months later than girls without indigenous surnames and with two indigenous surnames (p < 0,001). In girls whose parents had lowest level of schooling, the difference increased to eight months later (p < 0,005). Conclusions: Age at menarche in the group with higher indigenous descent is later even if socio-economic conditions remain stable. Genetic factors might play an important role, however conditions of vulnerability can influence and further delay the onset of reproductive competency.

[Age at menarche and indigenous ancestry: a population study in Chile]. / Edad de menarquia y ascendencia indígena: un estudio poblacional en Chile.

BACKGROUND: The age at menarche may influence decisively health and disease in women. It also indicates the beginning of the reproductive period and, as a consequence, the possibility of biological continuity for the human species. Genetic and environmental determinants define the age of menarche and can explain differences found among different populations. AIM: To determine the age at menarche among adolescents with different levels of indigenous descent (parental indigenous surnames), considering the effect of socioeconomic and demographic factors. MATERIAL AND METHODS: An observational study of historic cohorts of 8.624 girls from the Araucanía Region (central-southern Chile) was carried out. Data were collected by health professionals using a previously validated questionnaire. Occurrence of menarche was estimated through survival analysis and compared between groups (according to indigenous parental surnames) adjusted for parents' income and educational level and provenance (rural/urban). RESULTS: Estimated median age of menarche was 151 months (95% Cl: 150-151). In female with four indigenous surnames, menarche occurred two months later than girls without indigenous surnames and with two indigenous surnames (p < 0,001). In girls whose parents had lowest level of schooling, the difference increased to eight months later (p < 0,005). CONCLUSIONS: Age at menarche in the group with higher indigenous descent is later even if socio-economic conditions remain stable. Genetic factors might play an important role, however conditions of vulnerability can influence and further delay the onset of reproductive competency.

Core symptoms that discriminate premenstrual syndrome.

OBJECTIVE: To identify core symptoms that discriminate premenstrual syndrome (PMS) in prospective daily diary ratings and determine the association of these symptoms with functional impairment. METHODS: The study analyzed prospective daily symptom ratings and functional impairment data provided by 1081 women who requested PMS treatment at an academic medical center. The data were obtained before any treatment procedures. A random-split sample design provided separate developmental and validation datasets. Logistic regression was used to identify a reduced set of symptoms that best discriminated PMS. The results were validated in a separate dataset. Optimal cutoff points in the symptom scores were identified for clinical use. RESULTS: Statistical modeling identified 6 symptoms that discriminated PMS and not PMS as well as 17 symptoms in daily diary ratings. The identified core symptoms included anxiety/tension, mood swings, aches, appetite/food cravings, cramps, and decreased interest in activities. The area under the curve (AUC) was 0.84 in both models. The sums of the premenstrual symptom scores also discriminated PMS and not PMS and correctly classified 84%-86% of the cases. CONCLUSIONS: Six symptoms rated in daily diaries discriminate between PMS and not PMS among women seeking treatment and are significantly associated with functional impairment. The findings suggest that the burden of daily diaries to confirm PMS can be reduced to a smaller number of symptoms that distinguish the patients who meet this requirement. Results also support the concept that a clinical diagnosis of PMS can be developed around a core symptom group.

Serum leptin concentrations during the menstrual cycle in Iranian healthy women.

Leptin, a circulating 16-kd polypeptide consisting of 167 amino acids, appears to be involved in the body weight homeostasis. Moreover leptin plays an important role for the reproductive system, early embryogenesis, and fat metabolism during pregnancy and puberty. Significant correlations have been found between leptin and sexual hormones, which is a cytokine and has hormonal properties. The aim of this study was to determine serum leptin levels during the menstrual cycle, and the association between serum leptin and reproductive hormones in young, healthy Iranian women. 42 healthy women volunteered for the study. They all had regular menstrual cycles, with cycle length varying between 26 and 32 days. None of them used oral contraceptives. All were of normal weight, with body mass index ( BMI) < 25 Kg/m2. Fasting blood samples were collected during the follicular phase, mid cycle and luteal phase of the menstrual cycle. FSH and LH were measured with coated tube immunoradiometric assay. Estrogen and progesterone were measured using antibody -coated tubes. Serum Leptin concentration were measured by Leptin (sandwich) ELISA. In menstruating women, serum leptin increased from 13.15+/-1.60 ng/ml in the early follicular phase to 16.57+/-1.68 ng/ml (P<0.01) at the luteal phase. Serum leptin concentration negatively correlated with LH and progesterone (P<0.05). Mean serum leptin levels correlated with body mass index (BMI) (r =0.78, P<0.001).

Race bias tracks conception risk across the menstrual cycle.

Although a considerable body of research explores alterations in women's mating-relevant preferences across the menstrual cycle, investigators have yet to examine the potential for the menstrual cycle to influence intergroup attitudes. We examined the effects of changes in conception risk across the menstrual cycle on intergroup bias and found that increased conception risk was positively associated with several measures of race bias. This association was particularly strong when perceived vulnerability to sexual coercion was high. Our findings highlight the potential for hypotheses informed by an evolutionary perspective to generate new knowledge about current social problems-an avenue that may lead to new predictions in the study of intergroup relations.

[Women, bodies, and Hebrew medieval medical literature]. / Mujeres, cuerpos y literatura médica medieval en hebreo.

This essay explores different views on the female body articulated within Hebrew medieval texts on women's health care. It also investigates whether texts also integrate women's own perceptions of their bodies, and of their needs and care. I have analysed how this genre of Hebrew literature understood two key issues in the construction of sexed bodies: menstruation and cosmetics.

Menstruation in Ulysses.

This article investigates James Joyce's fascination with a wide variety of medical texts, sexual folklores, religious beliefs, and persistent superstitions about menstruation. That fascination finds its way into Ulysses, which draws upon a number of intertexts to inform a curiosity about the female body most strikingly articulated by Bloom, Molly, and Gerty MacDowell. These intertexts are not simply imported into the novel but are dismantled and interrogated, as Joyce exposes, rather than endorses, clichés of essential femininity.

Helping midlife women predict the onset of the final menses: SWAN, the Study of Women's Health Across the Nation.

OBJECTIVE: Women approaching menopause often ask their doctors, "When are my periods going to end?" The objective of this study was to predict time to the final menstrual period (FMP). DESIGN: This multiethnic, observational cohort study, the Study of Women's Health Across the Nation, has been ongoing since 1996. Data collected from seven annual study visits were used. The community-based cohort from seven national sites included 3,302 white, African American, Hispanic, Chinese, and Japanese women aged 42 to 52 years at baseline with a uterus and at least one ovary, who were not pregnant or taking reproductive hormones, and had at least one menstrual period within the past 3 months at baseline. The time to the FMP was defined retrospectively after 12 months of amenorrhea. Uni- and multivariable Cox proportional hazard models, hazard ratios (HRs), and 95% CIs were computed for variables of interest. RESULTS: A total of 2,662 women, of whom 706 had an observed FMP, were included. Age, menstrual cycles that had become farther apart (HR = 2.56, 95% CI = 1.94-3.39) or more variable (HR = 1.79, 95% CI = 1.45-2.21), and current smoking (HR = 1.68, 95% CI = 1.35-2.08) were all associated with shorter time to the FMP. Higher (log) follicle-stimulating hormone (HR = 2.32, 95% CI = 2.02-2.67) was related to a shorter time to the FMP, but the highest estradiol category (>or=100 pg/mL [367 pmol/L]) was associated with an earlier onset of the FMP (HR = 2.16, 95% CI = 1.63-2.89). The number of vasomotor symptoms was related to an earlier FMP, whereas higher physical activity and educational levels were associated with a later FMP. CONCLUSIONS: Age, menstrual cycle recall, smoking status, and hormone measurements can be used to estimate when the FMP will occur, allowing for more precise estimates for older midlife women: in the most extreme cases, ie, age 54, high estradiol level, current smoking, and high follicle-stimulating hormone level, the FMP can be estimated to within 1 year.

Characterizing daily urinary hormone profiles for women at midlife using functional data analysis.

The availability of daily hormone values for entire menstrual cycles offers an opportunity to apply new analytic techniques that confirm current knowledge and provide new insights into patterns of changing hormone profiles in women as they transition to the menopause. The Study of Women's Health Across the Nation (SWAN) collected urine samples during 1997-1999 from one menstrual cycle or up to 50 days from 848 women who live in seven cities across the United States. These samples were assayed for the urinary forms of estrogen, progesterone, follicle-stimulating hormone, and luteinizing hormone. The authors used functional data analysis to study variability in the hormone patterns of 572 of the 848 pre- and early-perimenopausal women with evidence of a luteal transition. Functional data analysis enabled the authors to identify asymmetries in women's hormone patterns related to cycle length that are not captured with single hormone value comparisons. Longer cycles were characterized by increasing dyssynchrony between follicle-stimulating hormone and luteinizing hormone in the luteal phase.