The relationship between obesity and race on inhibin B during the menopause transition

A high-fat eucaloric diet induces reprometabolic syndrome of obesity in normal weight women

We examined the effects of 1 month of a eucaloric, high-fat (48% of calories) diet (HFD) on gonadotropin secretion in normal-weight women to interrogate the role of free fatty acids and insulin in mediating the relative hypogonadotropic hypogonadism of obesity. Eighteen eumenorrheic women (body mass index [BMI] 18-25 kg/m2) were studied in the early follicular phase of the menstrual cycle before and after exposure to an HFD with frequent blood sampling for luteinizing hormone (LH) and follicle-stimulating hormone (FSH), followed by an assessment of pituitary sensitivity to gonadotropin-releasing hormone (GnRH). Mass spectrometry-based plasma metabolomic analysis was also performed. Paired testing and time-series analysis were performed as appropriate. Mean endogenous LH (unstimulated) was significantly decreased after the HFD (4.3 ± 1.0 vs. 3.8 ± 1.0, P < 0.01); mean unstimulated FSH was not changed. Both LH (10.1 ± 1.0 vs. 7.2 ± 1.0, P < 0.01) and FSH (9.5 ± 1.0 vs. 8.8 ± 1.0, P < 0.01) responses to 75 ng/kg of GnRH were reduced after the HFD. Mean LH pulse amplitude and LH interpulse interval were unaffected by the dietary exposure. Eucaloric HFD exposure did not cause weight change. Plasma metabolomics confirmed adherence with elevation of fasting free fatty acids (especially long-chain mono-, poly-, and highly unsaturated fatty acids) by the last day of the HFD. One-month exposure to an HFD successfully induced key reproductive and metabolic features of reprometabolic syndrome in normal-weight women. These data suggest that dietary factors may underlie the gonadotrope compromise seen in obesity-related subfertility and therapeutic dietary interventions, independent of weight loss, may be possible.

Association of body mass index with serum anti-Müllerian hormone and inhibin B levels among 8323 women attending a reproductive medical center: a cross-sectional study

PURPOSE

To assess the association of body mass index (BMI) with serum anti-Müllerian hormone (AMH) and inhibin B (InB) levels among women attending a reproductive medical center.

METHODS

We conducted a cross-sectional study of 8323 women (96.4% were Han race) without polycystic ovary syndrome (PCOS) from the reproductive medical center of Tongji Hospital in Wuhan, China for assisted reproductive technology treatment between January 2016 and May 2018. For each participant, BMI and levels of serum AMH and InB were measured at entry by trained clinical technicians. Multivariate linear regression models were used to quantitatively estimate the associations of continuous and categorical BMI with serum AMH and InB levels.

RESULTS

Each 1 kg/m² increase in BMI was significantly associated with a 1.02% (95% CI: 0.40, 1.65%) and 3.59% (3.11, 4.06%) reduction in AMH and InB levels, respectively. No departure from linearity was observed for either AMH or InB (both P for nonlinear trend >0.05). Overweight and obesity were significantly associated with a 6.01% (0.70, 11.04%) and 18.64% (2.29, 32.26%) reduction in AMH level, and were significantly associated with a 18.80% (15.23, 22.23%) and a 35.44% (25.47, 44.08%) reduction in InB level, respectively. In addition, the association between BMI and AMH level was significantly stronger among women ≥32 years.

CONCLUSIONS

BMI was linearly and inversely associated with AMH and InB levels among women without PCOS. Both overweight and obesity were significantly associated with lower AMH and InB levels.

[How to diagnose menopause? Postmenopausal women management: CNGOF and GEMVi clinical practice guidelines]

The diagnosis of menopause is sometimes difficult. The objective of this chapter is to describe the process of diagnosing menopause in a physiological situation, then in different clinical situations: women using hormonal contraception (per os, implant or intrauterine device), women with a history of hysterectomy, women previously treated for cancer. A review of the literature was carried out via Pubmed, Medline and Cochrane Library. The recommendations of international societies were also taken into account: International Menopause Society (IMS) https://www.imsociety.org, European Menopause and Andropause Society (EMAS) https://www.emas-online.org. In a classic situation, the diagnosis of menopause is a clinical diagnosis, made retrospectively, based on a 12-month period of consecutive amenorrhoea in a compatible age group (after 45 years of age). No hormonal dosage or imaging is indicated to make a diagnosis of menopause in a classic situation. In women using oestroprogestogen or progestative-only-pill contraception, implant, or Levonorgestrel-intrauterine device (LNG IUD), hormonal assays or pelvic ultrasound are neither recommended to make a diagnosis of menopause (grade C), nor to decide to stop contraception (grade C). The proposed strategy is the discontinuation of oral contraception, removal of the implant or LNG-IUD, and clinical follow-up (occurrence of amenorrhea) (expert opinion). In women with a history of hysterectomy, in the absence of evaluable clinical symptoms (amenorrhea), a repeat FSH≥40 combined with low estradiol (<20pg/ml) at least 3 months after the procedure could be a diagnostic orientation towards menopausal status. After cancer, in women who have received gonadotoxic treatment, the classic clinical criteria of 12 months of amenorrhea cannot be used to make a diagnosis of menopause with certainty (expert opinion). No further examination can be recommended to make a definite diagnosis of menopause (expert opinion). In breast cancer, the hormonal status to be taken into account when choosing initial hormone therapy is the one found before starting any treatment. If at the time of diagnosis of breast cancer the menopausal status is not known due to hormonal contraception, it is preferable to consider the patient as non-menopausal by default for the choice of hormone therapy for the cancer.

Association of waist-to-height ratio with estimated glomerular filtration rate in middle-aged and elderly Chinese

OBJECTIVE

This study aimed to assess the relationship between waist-to-height (WHtR) and estimated glomerular filtration rate (eGFR) in men, non-menopausal, and postmenopausal women among middle-aged and elderly Chinese.

METHODS

This study analyzed the data of 7,807 participants in a cross-sectional survey, ie, the third wave of the China Health and Retirement Longitudinal Study. Restrictive cubic-spline regression with three knots was used to assess the dose-response association of WHtR with eGFR. Piecewise linear regression models were further established to calculate the slope of each segment and their 95% confidence interval (CI).

RESULTS

After adjusting for potential confounders, an inverse L-shaped dose-response relationship was found between WHtR and eGFR among men (Pnonlinear = 0.024, threshold = 0.513) and postmenopausal women (Pnonlinear = 0.009, threshold = 0.503). The slopes on the right sides of the threshold were statistically significant among men (β2 = -33.77, 95% CI: -53.23 to -14.31) and postmenopausal women (β2 = -36.53, 95% CI: -49.71 to -23.35), respectively. A weak negative linear relationship existed between WHtR and eGFR in non-menopausal women.

CONCLUSIONS

The relationship between WHtR and eGFR tended to be inverse-L-shaped in men and postmenopausal women, but may vary with postmenopausal status in women.

Effect of aging, menopause, and age at natural menopause on the trend in body mass index: a 15-year population-based cohort

OBJECTIVE

To observe the effects of menopause, age at natural menopause (ANM), and aging on the trend in body mass index (BMI).

DESIGN

Prospective cohort with a 15-year follow-up of 929 women. Data obtained from the Tehran Lipid and Glucose Study.

SETTING

Not applicable.

INTERVENTION(S)

none.

PARTICIPANT(S)

Of women participating in the Tehran Lipid and Glucose Study, 929 who were reproductive during the study and menopaused at the last follow-up were included. Anthropometric data were measured repeatedly every 3 years, and the trend in BMI, associated with menopause and ANM, was tested using the generalized estimating equation.

MAIN OUTCOME MEASURE(S)

Body mass index in each follow-up session.

RESULT(S)

The adjusted model of the generalized estimating equation illustrates that BMI increases by age (β = 0.16) and menopausal status (β = 1.11). It also shows that women with higher ANM experienced a decreasing BMI (β = -0.03) compared with women with lower ANM. The interaction term of menopause and time (menopause × time) has a negative effect on BMI; that is, the usual increase in BMI after menopause is attenuated by time. (β = -0.4, 95% confidence interval -0.6, -0.3).

CONCLUSION(S)

Menopause and aging are independently correlated with increasing BMI. The trend in BMI, however, depends on the ANM of study participants: women with higher ANM than mean ANM of our population (i.e., 49 years) face a decreasing BMI compared with those with lower ANM.

The effects of hysterectomy with bilateral salpingectomy on ovarian reserve

OBJECTIVE

To determine whether ovarian reserve is compromised after hysterectomy with bilateral salpingectomy.

METHODS

A prospective longitudinal study was conducted among 84 women who underwent hysterectomy with bilateral salpingectomy at a tertiary medical center in Beijing, China, between August 2, 2015, and January 15, 2017. Serum levels of anti-Müllerian hormone (AMH) and follicle-stimulating hormone (FSH) were measured to assess ovarian function before undergoing the procedure (baseline) and at weeks 1 and 6 after surgery (postoperative period).

RESULTS

The median age was 41.61 ± 0.62 years. Age negatively correlated with the serum AMH level at baseline (P<0.001), as well as with preoperative-to-postoperative changes in the concentration of this hormone (P<0.001). Serum AMH levels were lower in the postoperative period versus the preoperative period (P<0.001). By contrast, serum FSH levels were higher in the postoperative period than in the preoperative period (P<0.001). Moreover, no correlation was found with body mass index.

CONCLUSIONS

Hysterectomy with bilateral salpingectomy compromised ovarian reserve, with the damage being most severe among younger patients.

Obesity Does not Compromise Ovarian Reserve Markers in Infertile Women

Introduction In the literature, conflicting results from studies examining the relationship between obesity and ovarian reserve have been reported. The purpose of the study is to investigate whether obesity adversely affects serum concentrations of ovarian reserve markers in infertile women with different ovarian reserve status. Materials and Methods A total of 402 women were assigned to three groups according to body mass index (BMI; < 25 kg/m ² : normal, n = 198; 25.0 - 29.9 kg/m ² : overweight, n = 126; and ≥ 30 kg/m ² : obese, n = 78). The women were also divided into two groups according to waist circumference (WC; < 80 cm: normal, n = 103; and ≥ 80 cm: obese, n = 299). Participants were also categorized into three types of ovarian reserve patterns: normal (n = 146), high (n = 112), and poor ovarian reserve (n = 144). The serum anti-Mullerian hormone (AMH), estradiol (E2), and follicle-stimulating hormone (FSH) levels were assayed and compared in all groups. Results There were no significant differences in BMI and WC in the three ovarian reserve groups. There were significant differences between all ovarian reserve groups for AMH, E2, and FSH (p < 0.001 for all). The comparisons of ovarian reserve parameters (AMH, E2, and FSH) and obesity parameters (BMI and WC) revealed no significant differences in women with all ovarian reserve patterns. Conclusion The parameters of ovarian reserve do not seem to be affected by increased BMI and WC. Thus, AMH may be considered as a reliable marker of ovarian reserve.

Liver X Receptors: A Possible Link between Lipid Disorders and Female Infertility

A close relationship exists between cholesterol and female reproductive physiology. Indeed, cholesterol is crucial for steroid synthesis by ovary and placenta, and primordial for cell structure during folliculogenesis. Furthermore, oxysterols, cholesterol-derived ligands, play a potential role in oocyte maturation. Anomalies of cholesterol metabolism are frequently linked to infertility. However, little is known about the molecular mechanisms. In parallel, increasing evidence describing the biological roles of liver X receptors (LXRs) in the regulation of steroid synthesis and inflammation, two processes necessary for follicle maturation and ovulation. Both of the isoforms of LXRs and their bona fide ligands are present in the ovary. LXR-deficient mice develop late sterility due to abnormal oocyte maturation and increased oocyte atresia. These mice also have an ovarian hyper stimulation syndrome in response to gonadotropin stimulation. Hence, further studies are necessary to explore their specific roles in oocyte, granulosa, and theca cells. LXRs also modulate estrogen signaling and this could explain the putative protective role of the LXRs in breast cancer growth. Altogether, clinical studies would be important for determining the physiological relevance of LXRs in reproductive disorders in women.

Effect of obesity and its related metabolic factors on serum anti-Müllerian hormone concentrations in women with and without polycystic ovaries

The relationship between serum anti-Müllerian hormone (AMH) levels, body mass index (BMI) and related metabolic factors were investigated in women with polycystic ovary syndrome (PCOS). A total of 691 women aged between 18 and 35 years, referred to the Department of Gynaecological Endocrinology at the University Hospital of Lille between 2009 and 2014 were included: 137 controls and 554 women with PCOS. Mean serum AMH levels were slightly but significantly lower in women with PCOS who were overweight or obese (BMI ≥25) compared with women of normal weight (BMI <25) (P < 0.05). No such difference was found in the control group. After bivariate analysis, no significant correlation was found between BMI and AMH in controls. In the PCOS group, this relationship was significant (P = 0.0001) but weak (r = -0.177). Stepwise multiple regression analysis yielded a significant model, including five variables (follicle count, serum androstenedione, BMI, serum LH and FSH) explaining 38.6%, 3.4%, 1.4%, 0.7% and 1.4% of the total serum AMH variance, respectively. No effect of metabolic status was found on serum AMH levels in controls, but a significant, albeit weak, negative independent correlation was found between AMH and BMI in women with PCOS.

Association of Mid-Life Changes in Body Size, Body Composition and Obesity Status with the Menopausal Transition

The mid-life period is a critical window for increases in body weight and changes in body composition. In this review, we summarize the clinical experience of the menopausal transition by obesity status, and examine the evidence regarding the menopausal transition and reproductive hormones effects on body weight, body composition, or fat distribution. Mid-life obesity is associated with a different menopausal experience including associations with menstrual cycle length prior to the final menstrual period (FMP), age at the FMP, and higher prevalence of vasomotor symptoms. The menopausal transition is associated with weight gain and increased central body fat distribution; the majority of evidence suggests that changes in weight are due to chronological aging whereas changes in body composition and fat distribution are primarily due to ovarian aging. Continuous and regular physical activity during mid-life may be an efficacious strategy to counteract the age-related and menopause-related changes in resting energy expenditure and to prevent weight gain and abdominal adiposity deposition.

Methods in a longitudinal cohort study of late reproductive age women: the Penn Ovarian Aging Study (POAS)

Background

This report describes the methods utilized in the Penn Ovarian Aging Study (POAS), which is a longitudinal cohort study of hormone dynamics and menopausal symptoms of women in the menopause transition.

Methods/Design

The cohort is a community-based sample of generally healthy women enrolled in the late reproductive years. The study population is a stratified random sample of African-American and Caucasian women, identified by random digit dialing.

Of the 1427 women who were identified as potentially eligible, 578 women were eligible after full screening; 75 % of the eligible women enrolled in the study (436/578). At Period 14 (14 years after study enrollment), 67 % remained active and were fully evaluated (293/436). Attrition was non-differential with respect to the sample characteristics.

The aims of the project overall are to 1) identify within-woman trends of reproductive hormones (estradiol, follicle stimulating hormone, hormone, lutinizing hormone, inhibin B, dehydroepiandrosterone, testosterone, and anti-mullerian hormone), cofactors such as race, body mass index (BMI), age, physical and behavioral symptoms, and their predictions of menopausal symptoms, and patterns around the final menstrual period; 2) identify associations of hormone dynamics with physical and behavioral symptoms that occur with ovarian aging and identify racial differences in these factors; 3) identify associations of genetic polymorphisms with levels and longitudinal trends in menopausal symptoms. The cohort consists of 436 late reproductive-age women at enrollment, and now has 18 years of approximately annual follow-up assessments. Menopausal stage based on concurrent menstrual dates is identified at each follow-up period.

Discussion

Studies of the cohort have shown that hot flashes can occur well before menopause and extend 10 or more years beyond menopause for sizeable numbers of women; provide evidence for new-onset depressed mood in the menopause transition and show that the final menstrual period is pivotal in the increases in depressive symptoms prior to menopause and decreases postmenopausal; suggest that poor sleep is common in the late reproductive years but increases in relation to the final menstrual period in only a small proportion of women; and show effects of obesity on reproductive hormones in the menopause transition. To date, more than 50 studies of the cohort are published in medical journals, demonstrating the relevance of these data to the clinical care of mid-life women.

Electronic supplementary material

The online version of this article (doi:10.1186/s40695-016-0014-2) contains supplementary material, which is available to authorized users.

Circulating anti-Müllerian hormone levels in relation to nutritional status and selected adipokines levels in polycystic ovary syndrome

OBJECTIVE

The aim of the study was to analyse the relationship between nutritional status, selected adipokines and plasma anti-Müllerian hormone (AMH) levels in women with polycystic ovary syndrome (PCOS).

STUDY DESIGN PATIENTS AND MEASUREMENTS

A prospective, cross-sectional study, involving 87 PCOS (48 obese) women and 67 non-PCOS women (36 obese). Anthropometric parameters were measured, and body composition was determined by the bioimpedance method. Fasting serum glucose, androgens, FSH, LH, SHBG, insulin, AMH, apelin-36, adiponectin, leptin and omentin-1 were measured.

RESULTS

Plasma AMH levels were significantly higher in PCOS compared to the non-PCOS group (7.8 ± 4.3 ng/ml vs 44 ± 2.4 ng/ml; P < 0.001). Furthermore, AMH levels were higher in both PCOS and non-PCOS normal weight than in obese subgroups (8.9 ± 4.4 ng/ml vs 7.0 ± 4.0 ng/ml; P < 0.05 and 5.1 ± 2.4 ng/ml vs 3.9 ± 2.3 ng/ml; P < 0.05). There were negative correlations between AMH levels and anthropometric parameters (body mass, BMI, fat mass and percentage, as well as waist circumference) and plasma omentin-1 concentrations (R = -0.28, P < 0.001; R = -0.30, P < 0.001; R = -0.36, P < 0.001; R = -0.34, P < 0.001; R = -0.23, P < 0.01; and R = -0.20, P < 0.05, respectively) in all study groups. In multiple regression analysis, circulating AMH level variability was explained by omentin-1 levels and anthropometric parameters (excluding waist circumference).

CONCLUSIONS

In this observational study, nutritional status appears to be the main factor influencing circulating AMH levels independent of PCOS. The observed AMH association with omentin-1 levels suggests that this adipokine may be a link between hormonal dysfunction of adipose tissue related to obesity and decreased AMH secretion.

Weight loss increases follicle stimulating hormone in overweight postmenopausal women [corrected]

OBJECTIVES

To examine the impact of a weight loss intervention upon follicle stimulating hormone (FSH) levels in postmenopause.

METHODS

Participants were postmenopausal, overweight, glucose-intolerant women not using exogenous estrogen (n = 382) in the Diabetes Prevention Program. Women were randomized to intensive lifestyle change (ILS) with the goals of weight reduction of at least 7% of initial weight and 150 min per week of moderate-intensity exercise, metformin 850 mg twice a day, or placebo administered twice a day.

RESULTS

Randomization to ILS led to small increases in FSH between baseline and 1-year follow-up vs. placebo (2.3 IU/l vs. -0.81 IU/l, P < 0.01). Increases in FSH were correlated with decreases in weight (r = -0.165, P < 0.01) and estradiol (E2) (r = -0.464, P < 0.0001) after adjustment for age, race/ethnicity, and randomization arm. Changes in FSH were still significantly associated with changes in weight even after adjustment for E2 levels. Metformin users had reductions in weight but non-significant changes in FSH and E2 levels vs. placebo.

CONCLUSIONS

Weight loss leads to small increases in FSH among overweight, postmenopausal women, potentially through pathways mediated by endogenous estrogen as well as other pathways.

Evidence that increased ovarian aromatase activity and expression account for higher estradiol levels in African American compared with Caucasian women

CONTEXT

Serum estradiol levels are significantly higher across the menstrual cycle in African American (AAW) compared with Caucasian women (CW) in the presence of similar FSH levels, yet the mechanism underlying this disparity is unknown.

OBJECTIVE

The objective of the study was to determine whether higher estradiol levels in AAW are due to increased granulosa cell aromatase mRNA expression and activity.

DESIGN

The design of the study included daily blood sampling and dominant follicle aspirations at an academic medical center during a natural menstrual cycle.

SUBJECTS

Healthy, normal cycling AAW (n = 15) and CW (n = 14) aged 19-34 years participated in the study.

MAIN OUTCOME MEASURES

Hormone levels in peripheral blood and follicular fluid (FF) aspirates and aromatase and FSH receptor mRNA expression in granulosa cells were measured.

RESULTS

AAW had higher FF estradiol [1713.0 (1144.5-2032.5) vs 994.5 (647.3-1426.5) ng/mL; median (interquartile range); P < .001] and estrone [76.9 (36.6-173.4) vs 28.8 (22.5-42.1) ng/mL; P < .001] levels than CW, independent of follicle size. AAW also had lower FF androstenedione to estrone (7 ± 1.8 vs 15.8 ± 4.1; mean ± SE; P = .04) and T to estradiol (0.01 ± 0.002 vs 0.02 ± 0.005; P = .03) ratios, indicating enhanced ovarian aromatase activity. There was a 5-fold increase in granulosa cell aromatase mRNA expression in AAW compared with CW (P < .001) with no difference in expression of FSH receptor. FSH, inhibin A, inhibin B, and AMH levels were not different in AAW and CW.

CONCLUSIONS

Increased ovarian aromatase mRNA expression, higher FF estradiol levels, and decreased FF androgen to estrogen ratios in AAW compared with CW provide compelling evidence that racial differences in ovarian aromatase activity contribute to higher levels of estradiol in AAW across the menstrual cycle. The absence of differences in FSH, FSH receptor expression, and AMH suggest that population-specific genetic variation in CYP19, the gene encoding aromatase, or in factors affecting its expression should be sought.

The complex interaction between obesity, metabolic syndrome and reproductive axis: a narrative review

The aim of this narrative review is to provide current evidence for the interaction between obesity, metabolic syndrome (MS) and reproductive axis. Gonadotropin-releasing hormone (GnRH) pulses and, consequently, normal function of reproductive (hypothalamus-pituitary-gonadal) axis depend on normal energy balance, which presupposes sufficient food intake, reasonable energy consumption and average thermoregulatory costs. In case of an energy imbalance, reproductive dysfunction may occur. In young women, excessive leanness is accompanied by puberty delay, whereas premature puberty might be a manifestation of obesity. In a similar way, obesity in men affects fertility. Excess adipose tissue results in increased conversion of testosterone to estradiol, which may lead to secondary hypogonadism through reproductive axis suppression. Moreover, oxidative stress at the level of the testicular micro-environment may result in decreased spermatogenesis and sperm damage. Products of the adipocyte, such as leptin, adiponectin and resistin, and gut peptides, such as ghrelin, are considered to be crucial in the interaction between energy balance and reproduction. Finally, an indirect evidence for the interplay between MS and reproductive axis is the fact that when treating components of one, parameters of the other can be improved as well. These therapeutic interventions include lifestyle modifications, pharmacological agents, such as sex hormone replacement therapy, and surgical procedures. Although many issues remain unclear, the elucidation of the complex interaction between MS and reproductive axis will have obvious clinical implications in the therapeutic approach of both entities.

Executive summary of the Stages of Reproductive Aging Workshop + 10: addressing the unfinished agenda of staging reproductive aging

OBJECTIVE

The aim of this article is to summarize the recommended updates to the 2001 Stages of Reproductive Aging Workshop (STRAW) criteria. The 2011 STRAW + 10 reviewed advances in understanding of the critical changes in hypothalamic-pituitary-ovarian function that occur before and after the final menstrual period.

METHODS

Scientists from five countries and multiple disciplines evaluated data from cohort studies of midlife women and in the context of chronic illness and endocrine disorders on change in menstrual, endocrine, and ovarian markers of reproductive aging including antimüllerian hormone, inhibin-B, follicle-stimulating hormone, and antral follicle count. Modifications were adopted by consensus.

RESULTS

STRAW + 10 simplified bleeding criteria for the early and late menopausal transition, recommended modifications to criteria for the late reproductive stage (Stage -3) and the early postmenopause stage (Stage +1), provided information on the duration of the late transition (Stage -1) and early postmenopause (Stage +1), and recommended application regardless of women's age, ethnicity, body size, or lifestyle characteristics.

CONCLUSIONS

STRAW + 10 provides a more comprehensive basis for assessing reproductive aging in research and clinical contexts. Application of the STRAW + 10 staging system should improve comparability of studies of midlife women and facilitate clinical decision making. Nonetheless, important knowledge gaps persist, and seven research priorities are identified.

Executive summary of the Stages of Reproductive Aging Workshop + 10: addressing the unfinished agenda of staging reproductive aging

OBJECTIVE

The aim of this article is to summarize the recommended updates to the 2001 Stages of Reproductive Aging Workshop (STRAW) criteria. The 2011 STRAW + 10 reviewed advances in understanding of the critical changes in hypothalamic-pituitary-ovarian function that occur before and after the final menstrual period.

METHODS

Scientists from five countries and multiple disciplines evaluated data from cohort studies of midlife women and in the context of chronic illness and endocrine disorders on change in menstrual, endocrine, and ovarian markers of reproductive aging including antimüllerian hormone, inhibin-B, follicle-stimulating hormone, and antral follicle count. Modifications were adopted by consensus.

RESULTS

STRAW + 10 simplified bleeding criteria for the early and late menopausal transition, recommended modifications to criteria for the late reproductive stage (Stage -3) and the early postmenopause stage (Stage +1), provided information on the duration of the late transition (Stage -1) and early postmenopause (Stage +1), and recommended application regardless of women's age, ethnicity, body size, or lifestyle characteristics.

CONCLUSIONS

STRAW + 10 provides a more comprehensive basis for assessing reproductive aging in research and clinical contexts. Application of the STRAW + 10 staging system should improve comparability of studies of midlife women and facilitate clinical decision making. Nonetheless, important knowledge gaps persist, and seven research priorities are identified.

Menstruation and the menopausal transition

This paper characterizes changes in menstrual bleeding during perimenopause,including bleeding changes that represent markers of the menopausal transition. Recent results from the Study of Women's Health Across the Nation and other cohort studies are reviewed. Emerging data describing subpopulation differences in the transition experience are highlighted. When treating women in the midlife, clinicians should pay careful attention to medical factors, including both conditions and treatments, that may increase menstrual blood loss or alter menstrual cycle characteristics sufficiently to obscure the onset of the menopausal transition or the final menstrual period.

Executive summary of the Stages of Reproductive Aging Workshop + 10: addressing the unfinished agenda of staging reproductive aging

OBJECTIVE

The aim of this article is to summarize the recommended updates to the 2001 Stages of Reproductive Aging Workshop (STRAW) criteria. The 2011 STRAW + 10 reviewed advances in understanding of the critical changes in hypothalamic-pituitary-ovarian function that occur before and after the final menstrual period.

METHOD(S)

Scientists from five countries and multiple disciplines evaluated data from cohort studies of midlife women and in the context of chronic illness and endocrine disorders on change in menstrual, endocrine, and ovarian markers of reproductive aging including antimüllerian hormone, inhibin-B, follicle-stimulating hormone, and antral follicle count. Modifications were adopted by consensus.

RESULT(S)

STRAW + 10 simplified bleeding criteria for the early and late menopausal transition, recommended modifications to criteria for the late reproductive stage (Stage -3) and the early postmenopause stage (Stage +1), provided information on the duration of the late transition (Stage -1) and early postmenopause (Stage +1), and recommended application regardless of women's age, ethnicity, body size, or lifestyle characteristics.

CONCLUSION(S)

STRAW + 10 provides a more comprehensive basis for assessing reproductive aging in research and clinical contexts. Application of the STRAW + 10 staging system should improve comparability of studies of midlife women and facilitate clinical decision making. Nonetheless, important knowledge gaps persist, and seven research priorities are identified.

Executive summary of the Stages of Reproductive Aging Workshop +10: addressing the unfinished agenda of staging reproductive aging

OBJECTIVE

The aim of this article is to summarize the recommended updates to the 2001 Stages of Reproductive Aging Workshop (STRAW) criteria. The 2011 STRAW +10 reviewed advances in understanding of the critical changes in hypothalamic-pituitary-ovarian function that occur before and after the final menstrual period.

METHODS

Scientists from five countries and multiple disciplines evaluated data from cohort studies of midlife women and in the context of chronic illness and endocrine disorders on change in menstrual, endocrine, and ovarian markers of reproductive aging including antimüllerian hormone, inhibin-B, follicle-stimulating hormone, and antral follicle count. Modifications were adopted by consensus.

RESULTS

STRAW +10 simplified bleeding criteria for the early and late menopausal transition, recommended modifications to criteria for the late reproductive stage (Stage -3) and the early postmenopause stage (Stage +1), provided information on the duration of the late transition (Stage -1) and early postmenopause (Stage +1), and recommended application regardless of women's age, ethnicity, body size, or lifestyle characteristics.

CONCLUSIONS

STRAW +10 provides a more comprehensive basis for assessing reproductive aging in research and clinical contexts. Application of the STRAW +10 staging system should improve comparability of studies of midlife women and facilitate clinical decision making. Nonetheless, important knowledge gaps persist, and seven research priorities are identified.

The reproductive endocrinology of the menopausal transition

The menopause transition is a dynamic process that begins with the first appearance of menstrual irregularity and ends with a woman's final menstrual period. As ovarian follicle numbers dwindle, the hypothalamic-pituitary-ovarian axis enters a state of compensated failure. In this state, elevated FSH is capable of maintaining relatively regular folliculogenesis and ovulation, but fertility is reduced. Eventually, this state of compensated failure cannot be sustained, and the ovary becomes unable to produce functioning follicles. Recent multicenter studies from several countries have addressed the pattern of change in hormones and a model form reproductive aging has been developed that helps explain the changes in hormone patterns and fertility that accompany menopause. Perhaps more important, the hormonal changes of the menopausal transition may be predictive of future disease risk. This review will undertake an explanation of the current literature on this topic.

Elevated body mass index is associated with lower serum anti-mullerian hormone levels in infertile women with diminished ovarian reserve but not with normal ovarian reserve

OBJECTIVE

To investigate the association between elevated body mass index (BMI) and ovarian reserve.

DESIGN

Cross-sectional study.

SETTING

Academic institutions.

PATIENT(S)

Two hundred ninety women with infertility. Diminished ovarian reserve (DOR) was defined as day 3 FSH>10 IU/L.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Random serum antimullerian hormone (AMH) levels and number of oocytes retrieved during assisted reproductive technology cycle.

RESULT(S)

Increasing BMI was associated with lower random serum AMH levels in infertile women with DOR but not in women with normal ovarian reserve (NOR). Among women with DOR, mean random serum AMH levels were 33% lower in overweight and obese women compared with women with normal weight. The same association was not true for women with NOR. Out of 290 women evaluated for infertility, 109 women underwent a controlled ovarian hyperstimulation (COH)-IVF cycle. Women with elevated BMI and DOR had lower number of oocytes retrieved compared with women with normal BMI and DOR (6.4±4.3 vs. 9.4±6), an association that was not observed among women with NOR.

CONCLUSION(S)

Overweight and obese women with DOR as defined by high day 3 serum FSH levels have lower serum AMH levels and number of oocytes retrieved compared with nonobese women with DOR.

Metabolic syndrome and oocyte quality

Metabolic syndrome affects one in four women in the USA, and the incidence is rising every year. Metabolic syndrome is strongly associated with development of coronary artery disease and diabetes. Women of reproductive age are not spared from the complications of metabolic syndrome, which overlaps with obesity and polycystic ovary syndrome (PCOS), both of which are linked to infertility and poor reproductive outcome. Therefore, the relationship between the metabolic syndrome and reproductive dysfunction is an active area of study. In this review, we discuss the animal and human data available to determine if the abnormality is at the level of the ovary and/or endometrium, and discuss the underlying mechanisms causing the associated poor reproductive outcomes.

Relating smoking, obesity, insulin resistance, and ovarian biomarker changes to the final menstrual period

To determine if smoking, obesity, and insulin resistance mediated age at final menstrual period (FMP), we examined anti-Müllerian hormone (AMH), inhibin B, and follicle-stimulating hormone (FSH) as biomarkers of changing follicle status and ovarian aging. We performed a longitudinal data analysis from a cohort of premenopausal women followed to their FMP. Our results found that smokers had an earlier age at FMP (P < 0.003) and a more rapid decline in their AMH slope relative to age at FMP (P < 0.002). Smokers had a lower baseline inhibin B level relative to age at the FMP than nonsmokers (P = 0.002). Increasing insulin resistance was associated with a shorter time to FMP (P < 0.003) and associations of obesity and time to FMP were observed (P = 0.004, in model with FSH). Change in ovarian biomarkers did not mediate the time to FMP. We found that smoking was associated with age at FMP and modified associations of AMH and inhibin B with age at FMP. Insulin resistance was associated with shorter time to FMP independent of the biomarkers. Interventions targeting smoking and insulin resistance could curtail the undue advancement of reproductive aging.

The impact of smoking on antimüllerian hormone levels in women aged 38 to 50 years

OBJECTIVE

Smoking is associated with increased follicle-stimulating hormone levels and early menopause. Smoking may directly accelerate ovarian follicular depletion or may act indirectly by increasing the pituitary production of follicle-stimulating hormone. Antimüllerian hormone (AMH), produced by ovarian follicles, is a more direct measure of ovarian reserve. The objective of our study was to determine the extent to which smoking influences ovarian reserve, as measured by AMH levels.

METHODS

A community sample of 284 women aged 38 to 50 years completed a self-administered questionnaire including a detailed smoking history. Serum AMH levels were measured on day 2, 3, or 4 of the menstrual cycle. The association between AMH and smoking was analyzed using linear regression, adjusting for age and body mass index.

RESULTS

Participants aged 38 to 42, 43 to 45, and 46 to 50 years had geometric mean AMH values of 6.7 pM (95% CI, 5.2-8.7 pM), 2.7 pM (95% CI, 1.9-3.8 pM), and 1.3 pM (95% CI, 1.0-1.7 pM), respectively. Current smokers, but not past smokers, had 44% lower AMH values than did the reference group (participants with neither active nor former or passive smoke exposure; P = 0.04). Passive smoking had no effect on AMH values when compared with the reference group (P = 0.55). The impact of smoking on AMH values was not dose dependent based on cigarettes per day (P = 0.08) or pack-years (P = 0.22). Finally, prenatal exposure to smoking (either maternal or paternal) had no impact on AMH levels (P = 0.47 and P = 0.89, respectively).

CONCLUSIONS

Active smoking, but not former smoking, is associated with decreased AMH values in late-reproductive-age and perimenopausal women, suggesting a possible direct effect of smoking on the depletion of the antral but not primordial follicles. The direct impact of active smoking on AMH levels in younger women requires further investigation.

Obesity and reproductive hormone levels in the transition to menopause

OBJECTIVE

The aim of this study was to estimate associations of obesity with reproductive hormone levels as women progress from premenopausal to postmenopausal status.

METHODS

This was a longitudinal study conducted in the population-based Penn Ovarian Aging Cohort (N = 436). At cohort enrollment, the women were premenopausal, ages 35 to 47 years, with equal numbers of African Americans and whites. Anthropometric measures, menopause status, and reproductive hormone measures were evaluated for 12 years. Associations of the anthropometric measures with estradiol, follicle-stimulating hormone, and inhibin B in the menopausal transition were estimated using generalized linear regression models for repeated measures.

RESULTS

Associations between obesity and hormone levels differed by menopause status as indicated by significant interactions between each hormone and menopausal stage. Premenopausal obese and overweight women had significantly lower estradiol levels compared with nonobese women, independent of age, race, and smoking (obese: 32.8 pg/mL [95% CI, 30.6-35.2] vs nonobese: 39.8 pg/mL [95% CI, 37.0-42.8], P < 0.001). The associations reversed postmenopause, with obese women having the highest estradiol levels (obese: 20.6 pg/mL [95% CI, 17.2-24.7] vs nonobese: 12.2 pg/mL [95% CI, 10.1-14.8], P < 0.001). Inhibin B levels were significantly lower in premenopausal obese compared with nonobese women but reversed in the late transition stage. Follicle-stimulating hormone levels were lowest in postmenopausal obese compared with nonobese women (P < 0.001). Measures of waist circumference (central adiposity) and waist-to-hip ratio paralleled the body mass index results.

CONCLUSION

Obesity is an important factor in hormone dynamics independent of age, race, and smoking in midlife women, although the mechanisms remain unclear.

Effect of cigarette smoking upon reproductive hormones in women of reproductive age: a retrospective analysis

There is continuing debate concerning the relationship between cigarette smoking and premature ovarian failure. The aim of this retrospective data analysis was to investigate whether smoking has a measurable effect on early follicular serum concentrations of inhibin B hormone, FSH and anti-Müllerian hormone (AMH) in women of reproductive age. A database containing data on age, smoking status and serum concentrations of inhibin B, FSH and AMH was analysed. Pearson's correlation coefficient was calculated to determine the correlation between hormone concentrations and age. One-way analysis of variance was used to determine any significant difference in age between smoking categories and a univariate general linear model was used to compare geometric means and geometric mean ratios of hormone concentrations in relation to smoking status. Serum concentrations of inhibin B were significantly lower in women who had ever smoked cigarettes: F(2,332) = 3.371, P = 0.036. There was no statistically significant difference in FSH or AMH concentrations although a trend towards lower AMH concentrations in smokers was observed. This analysis provides evidence of an advancement of ovarian ageing in women who smoke cigarettes and is relevant to women of childbearing age who wish to avoid premature decline in fertility.

Normal serum concentrations of anti-Müllerian hormone in women with regular menstrual cycles

Anti-Müllerian hormone (AMH) has become the 'molecule of the moment' in the field of reproductive endocrinology. Indeed, it is valuable as a means of increasing understanding of ovarian pathophysiology and for guiding clinical management across a broad range of conditions. However, no normative values have been established for circulating AMH in healthy women. In this cross-sectional study, 277 healthy females (aged 18-50 years) were included. AMH was measured by commercial enzyme-linked immunosorbent assay. Serum AMH concentrations show a progressive decline with female ageing. The age-related changes in AMH were best fitted by a polynomial function. Mean AMH concentrations were not modified by past use of oral contraceptive and were independent of parity of women. Age-specific normative values for circulating AMH concentration were established. AMH concentrations seem to be independent of the reproductive history of the patient.

Racial and ethnic differences in reproductive potential across the life cycle

OBJECTIVE

To review variations in specific reproductive health outcomes by race and ethnicity. A growing number of reports have explored potential gaps in the quality of reproductive health and healthcare across racial and ethnic groups. Diverse results from numerous investigations have made it challenging for practitioners to confirm the significance of these disparities.

METHOD(S)

Three specific areas of the reproductive life cycle were examined: pubertal onset, outcomes from treatment with assisted reproductive technologies (ART), and the menopausal transition. These areas were selected as they encompass a continuum of events across the reproductive life span of women. Outcomes were compared in black, white, Asian, and Hispanic women. Medline searches querying on keywords puberty, IVF, ART, menopause, menopausal symptoms, racial disparity, race, Asian, Japanese, Chinese, African American, black, Hispanic, and Latino were performed to isolate relevant publications for review.

RESULT(S)

Differences across race and ethnicity were noted in each clinical endpoint. The most notable findings included earlier puberty in blacks and Hispanics compared with whites, significantly lower live birth rates after ART in all racial and ethnic groups compared with whites, and differences in perimenopausal symptomatology and possibly timing in various racial/ethnic groups compared with whites. Additional research is needed to completely unravel the full significance and basic underpinnings of these disparities. Some of the limitations of the current state of the literature in drawing conclusions about the independent effect of race/ethnicity on reproductive disparities include small samples sizes in some studies, inconsistencies in the characterization of racial/ethnic groups, and incomplete control of potential confounding.

CONCLUSION(S)

Race and ethnicity appear to be important correlates of outcomes from the initiation of reproduction functioning through to its conclusion. The ultimate goal of identifying racial disparities in reproduction is to isolate the basic determinants of disparities and formulate strategies to improve outcomes for women at risk. The differences demonstrated in this review of the literature could represent environmental, sociocultural, and/or genetic correlates of race that influence these important milestones.

Antimullerian hormone and obesity: insights in oral contraceptive users

BACKGROUND

The study was conducted to examine the impact of oral contraceptives (OCs) on serum antimullerian hormone (AMH) levels by obesity status in reproductive-age women.

STUDY DESIGN

Ovulatory women, ages 18-35 years, of normal (<25 kg/m(2); n=10) and obese (>30 kg/m(2); n=10) body mass index (BMI) received a low-dose OC (20 mcg ethinyl estradiol/100 mcg levonorgestrel) for two cycles. Serum samples obtained at several time points during active pill use and hormone-free intervals were analyzed for AMH, follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol and inhibin B.

RESULTS

AMH levels did not differ by OC cycle day in either BMI group. On average, AMH levels were 34% lower in the obese group (2.9+/-2.1 vs. 4.4+/-1.8 ng/mL, p<.05). Modeling to determine differences in AMH throughout the cycle based on obesity status demonstrated significantly lower levels (p<.05), whereas serum AMH, FSH, LH, estradiol and inhibin B levels revealed no correlations when all time points were included.

CONCLUSIONS

In reproductive-age women, serum AMH levels do not appear to fluctuate during OC use, but AMH levels are significantly lower in obese women. Lower levels do not appear to be due to differences in gonadotropin levels or ovarian activity.

Clinical implications of ovarian reserve testing

Serum and urinary markers of ovarian reserve, follicular phase inhibin B, follicle stimulating hormone, and antimullerian hormone levels, are physiologically associated with ovarian aging, decline with chronologic age, and appear to predict later stages of reproductive aging including the menopause transition and menopause. In infertile women, they can be used to predict low oocyte yield and treatment failure in women undergoing in vitro fertilization. These markers seem to be affected by common ovarian toxicants, such as smoking, which advance the age at menopause. Although available for commercial use, home test kits have not been shown to predict fertility or infertility in the general population. Clinical use of these markers is limited by the variety of assays, lack of definitive thresholds, and their intercycle variability in older women. Results should be conveyed with caution when highly discrepant with age, in the obese, and in women with irregular menstrual cycles. Further research is needed to assess their predictive value for determining fertility in the general population.

Body size affects measures of ovarian reserve in late reproductive age women

OBJECTIVE

To examine the association between obesity and serum and ultrasound measures of ovarian reserve in late reproductive age women.

DESIGN

Cross-sectional study of 36 healthy women, ages 40 to 52 years. Women were recruited in a 1:1 ratio of normal weight (body mass index <25) to obese women (body mass index >or=30). Early follicular phase blood draw, anthropometric measurements, and a transvaginal ultrasonography were performed. Outcome measures were serum antimullerian hormone, inhibin B, estradiol, follicle-stimulating hormone, ultrasound ovarian volume, and antral follicle count.

RESULTS

Mean antral follicle count was 7.6 for normal weight and 6.3 for obese women (P = 0.35). Proportions of normal weight (17%) versus obese women (22%) with antral follicle count less than 4 were similar. Ovarian volumes did not differ by body size. In adjusted models, antimullerian hormone levels in obese women were 77% lower on average than those in normal weight women (P = 0.02). Inhibin B levels were 24% lower in obese women compared with normal weight women (P = 0.08). Follicle-stimulating hormone and estradiol were not associated with body mass index.

CONCLUSIONS

Although antral follicle count did not differ by body size, antimullerian hormone was lower in obese compared with normal weight late reproductive age women. These data suggest that lower antimullerian hormone levels in obese late reproductive age women result from physiologic processes other than decreased ovarian reserve.

The role of mullerian inhibiting substance in female reproduction

PURPOSE OF REVIEW

To review the role of mullerian inhibiting substance in the context of female reproduction.

RECENT FINDINGS

Serum and follicular fluid mullerian inhibiting substance can be measured by commercially available enzyme-linked immunosorbent assay kits. Mullerian inhibiting substance is secreted from small antral follicles with minimal fluctuation throughout the menstrual cycle. The exact biological functions of mullerian inhibiting substance are uncertain; however, mullerian inhibiting substance most likely mediates follicle recruitment and selection, and may inhibit aromatase activity. Most data suggests an interaction between follicle-stimulating hormone, and mullerian inhibiting substance although the exact nature of the relationship is unknown. Mullerian inhibiting substance is characteristically elevated in polycystic ovarian syndrome, and may be associated with other features of polycystic ovary syndrome such as insulin resistance, hyperandrogenemia, and the degree of anovulation. Mullerian inhibiting substance changes have also been associated with functional hypothalamic amenorrhea, premature ovarian failure, endometriosis and obesity. Mullerian inhibiting substance has been studied extensively in the context of in-vitro fertilization and has been correlated with several outcome parameters.

SUMMARY

Mullerian inhibiting substance is gaining acceptance as a useful marker of female reproductive function, especially with ovulatory disorders and IVF outcomes. Mullerian inhibiting substance offers several advantages to existing screening tests, but establishment of an assay standard should be considered before widespread clinical implementation becomes viable.

Statistically significant changes of antimüllerian hormone and inhibin levels during the physiologic menstrual cycle in reproductive age women

OBJECTIVE

To define the dynamics of antimüllerian hormone (AMH) and inhibins during the physiologic menstrual cycle.

DESIGN

Longitudinal study.

SETTING

University hospital.

PATIENT(S)

36 young, healthy, normal weight Caucasian women without medication.

INTERVENTION(S)

Normal ovulatory menstrual cycles were evaluated by regular blood sampling taken every other day and periovulatory every day.

MAIN OUTCOME MEASURE(S)

Serum concentrations of AMH, inhibin A and B, follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin, estradiol, progesterone, and free testosterone were measured in all blood samples.

RESULT(S)

Median AMH levels are statistically significantly higher in the late follicular compared with ovulation or the early luteal phase. There are statistically significant correlations between both AMH and FSH, and AMH and free testosterone in all cycle phases. Inhibin A increases strongly in the late follicular phase and peaks at day LH + 4. Inhibin B shows a broad midfollicular and a sharp early luteal peak, the difference being statistically significant between day LH + 4 and the earlier time points and between day LH + 2 and day LH. Although there is a negative association between inhibin A or B and the body mass index (BMI), there is no correlation between AMH and the BMI.

CONCLUSION(S)

Levels of AMH show a statistically significant change during the menstrual cycle and may influence the circulating gonadotropin and steroid hormone levels.

Association of anti-mullerian hormone levels with obesity in late reproductive-age women

OBJECTIVE

To describe anti-mullerian hormone (AMH) levels in healthy late reproductive age women and test the hypothesis that AMH levels are lower in obese compared to non-obese women.

DESIGN

Cross-sectional study of AMH levels. Longitudinal analysis of a subgroup with 10 AMH measures over 8 years to support the cross-sectional results.

SETTING

A population-based cohort of healthy late reproductive-age women.

PARTICIPANTS

Selected from the cohort to provide comparisons of body mass index (BMI), menopausal status, age and race (n = 122).

INTERVENTIONS

AMH levels were determined from blood samples collected in the parent study.

MAIN OUTCOME MEASURE

Serum levels of AMH.

RESULTS

AMH levels were 65% lower in obese women compared to non-obese women (0.016 ng/mL and 0.046 ng/mL, respectively). The geometric mean ratio was 0.35; 95% CI 0.13, 0.92, P=.034. AMH levels were significantly lower in the menopausal transition compared to premenopausal women and were significantly lower in all age groups > or =40 years compared to the 35-39 year-old women. BMI remained significantly associated with AMH levels in multivariable models that included adjustments for menopausal status, age, race and cycle day. In the longitudinal analysis of a subgroup, obese women had significantly lower mean AMH levels over the 8-year interval compared to the non-obese women (0.459 ng/mL; CI 0.28, 0.75 and 0.566 ng/mL; CI 0.34, 0.94, respectively; P=.016), corroborating the cross-sectional study results.

CONCLUSIONS

Obese women have lower AMH levels compared to non-obese women in the late reproductive years. The findings offer further evidence of the complex relationships between obesity and reproductive hormone levels in women.

The influence of depression, body mass index, and smoking on serum inhibin B levels in late reproductive-aged women

CONTEXT

Women experiencing depression have difficult psychosocial functioning, and recent data suggest an earlier onset of menopause. Understanding the biological mechanism for the impairment of reproductive function associated with depression is important.

OBJECTIVE

The objective of the study was to determine whether a lifetime history of depression is associated with reduced ovarian reserve as reflected in serum levels of the granulosa cell product, inhibin B.

DESIGN

Residual serum samples from a subset of patients in the Harvard Study of Cycles and Moods were collected.

SETTING

Patients were recruited from seven Boston-area communities.

PATIENTS

Women with or without a history of major depression, based on structured clinical interviews for Diagnostic and Statistical Manual of Mental Disorders, fourth edition, were enrolled. A subset of patients who had provided an early follicular phase blood specimen at study enrollment and two or more other samples over the first 18-month period of follow-up were included.

INTERVENTION

There were no interventions.

MAIN OUTCOME MEASURE

Serum inhibin B levels were measured.

RESULTS

Serum FSH levels were higher in women with a history of depression, whereas inhibin B levels did not differ between groups. Body mass index and age were significantly and inversely related to serum inhibin B levels. Smoking history was noted, for the first time, to have a significant negative association with inhibin B levels.

CONCLUSIONS

Smoking has a direct negative effect on ovarian reserve, as suggested by decreased serum inhibin B levels. In contrast, effects of depression on the reproductive axis may occur at the level of the pituitary and/or hypothalamus rather than at the gonadal level, as suggested by increased serum FSH levels.