Climacteric and fibromyalgia: a review

Fibromyalgia (FM) and climacteric conditions share common epidemiological and clinical features, with FM symptoms often beginning during menopause. Musculoskeletal pain, arthralgia, myalgia and other symptoms are frequently seen in both conditions. Some research suggests a link between the cessation of sex hormones and FM symptoms. Women with FM tend to experience more severe symptoms after menopause, and the severity of FM symptoms can worsen in women who have had a hysterectomy with or without oophorectomy. Despite these similarities, it is essential to treat FM and climacteric conditions separately and follow established guidelines for management. However, it is also important to recognize that both conditions can coexist in the same patient. It is crucial to note that there is limited evidence supporting the effectiveness of menopausal hormone therapy for primary FM management. Therefore, menopausal hormone therapy should not be recommended for FM unless the patient also has climacteric syndrome.

Musculoskeletal pain among Chinese women during the menopausal transition: findings from a longitudinal cohort study

ABSTRACT

The profiles of muscle and joint pain throughout the menopausal transition and the factors associated with these symptoms have not been determined. A total of 609 participants from a longitudinal cohort study conducted in an urban Chinese community were enrolled in this study. We assessed the prevalence of musculoskeletal symptoms at different menopausal stages and explored the factors associated with these symptoms. The prevalence and severity of muscle and joint pain increase as menopausal stages progress, and late menopausal transition may be a crucial timepoint that triggers the onset of musculoskeletal pain. The results of the multivariate analysis revealed that poor health status (OR = 2.245, 95% CI = 1.714-2.94, P < 0.001), body mass index (BMI) (OR = 1.046, 95% CI = 1.01-1.084, P = 0.011), the presence of anxiety (OR = 1.601, 95% CI = 1.211-2.117, P < 0.001), and depression (OR = 1.368, 95% CI = 1.143-1.639, P < 0.001) were independently associated with muscle and joint pain. In addition, the severity of musculoskeletal pain was related to poor health status (OR = 2.738, 95% CI = 1.91-3.924, P < 0.001) and depression (OR = 1.371, 95% CI = 1.095-1.718, P = 0.006). Musculoskeletal symptoms are frequent somatic symptoms experienced by Chinese middle-aged women. Women with poor health status, high BMI, anxiety, and depression were at heightened risk of experiencing musculoskeletal pain. The severity of pain increased over time.

Fibromyalgia and menopause: an open study on postmenopausal hormone therapy

BACKGROUND

Fibromyalgia women (FM) seems to get worse at menopause suggesting some influence of estrogens on its pathophysiology. We aimed to study the influence of postmenopausal hormone therapy (HT) in FM, the relationship with sleep and FM impact.

METHODS

We analyzed prospectively 69 menopausal women, divided in two groups, FM group (FMG; N.=32) and comparison group (CG; N.=28) submitted to HT for twelve weeks (1.2 mg/g transdermal estradiol, 100 mg micronized natural progesterone oral/daily). Data on Utian Quality of Life Questionnaire (UQOL) and Pittsburgh Sleep Quality Index (PSQI) were obtained in both groups, at entrance and twelve weeks after HT. FM patients also completed the Fibromyalgia Impact Questionnaire - Revised (FIQ-R) and fibromyalgia severity (FS).

RESULTS

FM patients improved significantly the FIQ-R (P=0.0001, median FIQ-R score 30% lower), mainly the severity of FM, assessed by FS (P<0.0001). Both groups had improved quality of life and sleep (UQOL: P=0.0001; P=0.001, PSQI: P<0.0001; P=0.007, respectively). Differences between first and second PSQI were greater for CG than for FMG (P=0.008).

CONCLUSIONS

HT improving sleep and quality of life in both groups; it was a significant clinical improvement seen by FIQ and FS in FM patients. These changes characterize improvement of functional status and symptoms severity.

Hormone therapy for sexual function in perimenopausal and postmenopausal women

BACKGROUND

The perimenopausal and postmenopausal periods are associated with many symptoms, including sexual complaints. This review is an update of a review first published in 2013.

OBJECTIVES

We aimed to assess the effect of hormone therapy on sexual function in perimenopausal and postmenopausal women.

SEARCH METHODS

On 19 December 2022 we searched the Gynaecology and Fertility Group Specialised Register, CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, LILACS, ISI Web of Science, two trials registries, and OpenGrey, together with reference checking and contact with experts in the field for any additional studies.

SELECTION CRITERIA

We included randomized controlled trials that compared hormone therapy to either placebo or no intervention (control) using any validated assessment tool to evaluate sexual function. We considered hormone therapy: estrogen alone; estrogen in combination with progestogens; synthetic steroids, for example, tibolone; selective estrogen receptor modulators (SERMs), for example, raloxifene, bazedoxifene; and SERMs in combination with estrogen.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recommended by Cochrane. We analyzed data using mean differences (MDs) and standardized mean differences (SMDs). The primary outcome was the sexual function score. Secondary outcomes were the domains of sexual response: desire; arousal; lubrication; orgasm; satisfaction; and pain. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included 36 studies (23,299 women; 12,225 intervention group; 11,074 control group), of which 35 evaluated postmenopausal women; only one study evaluated perimenopausal women. The 'symptomatic or early postmenopausal women' subgroup included 10 studies, which included women experiencing menopausal symptoms (symptoms such as hot flushes, night sweats, sleep disturbance, vaginal atrophy, and dyspareunia) or early postmenopausal women (within five years after menopause). The 'unselected postmenopausal women' subgroup included 26 studies, which included women regardless of menopausal symptoms and women whose last menstrual period was more than five years earlier. No study included only women with sexual dysfunction and only seven studies evaluated sexual function as a primary outcome. We deemed 20 studies at high risk of bias, two studies at low risk, and the other 14 studies at unclear risk of bias. Nineteen studies received commercial funding. Estrogen alone versus control probably slightly improves the sexual function composite score in symptomatic or early postmenopausal women (SMD 0.50, 95% confidence interval (CI) (0.04 to 0.96; I² = 88%; 3 studies, 699 women; moderate-quality evidence), and probably makes little or no difference to the sexual function composite score in unselected postmenopausal women (SMD 0.64, 95% CI -0.12 to 1.41; I² = 94%; 6 studies, 608 women; moderate-quality evidence). The pooled result suggests that estrogen alone versus placebo or no intervention probably slightly improves sexual function composite score (SMD 0.60, 95% CI 0.16 to 1.04; I² = 92%; 9 studies, 1307 women, moderate-quality evidence). We are uncertain of the effect of estrogen combined with progestogens versus placebo or no intervention on the sexual function composite score in unselected postmenopausal women (MD 0.08 95% CI -1.52 to 1.68; 1 study, 104 women; very low-quality evidence). We are uncertain of the effect of synthetic steroids versus control on the sexual function composite score in symptomatic or early postmenopausal women (SMD 1.32, 95% CI 1.18 to 1.47; 1 study, 883 women; very low-quality evidence) and of their effect in unselected postmenopausal women (SMD 0.46, 95% CI 0.07 to 0.85; 1 study, 105 women; very low-quality evidence). We are uncertain of the effect of SERMs versus control on the sexual function composite score in symptomatic or early postmenopausal women (MD -1.00, 95% CI -2.00 to -0.00; 1 study, 215 women; very low-quality evidence) and of their effect in unselected postmenopausal women (MD 2.24, 95% 1.37 to 3.11 2 studies, 1525 women, I² = 1%, low-quality evidence). We are uncertain of the effect of SERMs combined with estrogen versus control on the sexual function composite score in symptomatic or early postmenopausal women (SMD 0.22, 95% CI 0.00 to 0.43; 1 study, 542 women; very low-quality evidence) and of their effect in unselected postmenopausal women (SMD 2.79, 95% CI 2.41 to 3.18; 1 study, 272 women; very low-quality evidence). The observed heterogeneity in many analyses may be caused by variations in the interventions and doses used, and by different tools used for assessment.

AUTHORS' CONCLUSIONS

Hormone therapy treatment with estrogen alone probably slightly improves the sexual function composite score in women with menopausal symptoms or in early postmenopause (within five years of amenorrhoea), and in unselected postmenopausal women, especially in the lubrication, pain, and satisfaction domains. We are uncertain whether estrogen combined with progestogens improves the sexual function composite score in unselected postmenopausal women. Evidence regarding other hormone therapies (synthetic steroids and SERMs) is of very low quality and we are uncertain of their effect on sexual function. The current evidence does not suggest the beneficial effects of synthetic steroids (for example tibolone) or SERMs alone or combined with estrogen on sexual function. More studies that evaluate the effect of estrogen combined with progestogens, synthetic steroids, SERMs, and SERMs combined with estrogen would improve the quality of the evidence for the effect of these treatments on sexual function in perimenopausal and postmenopausal women.

Efficacy of mecobalamin (vitamin B12) in the treatment of long-term pain in women diagnosed with fibromyalgia: protocol for a randomised, placebo-controlled trial

INTRODUCTION

Fibromyalgia causes long-term pain. It affects at least 2% of the population, the majority being women. In addition, extended symptoms corresponding to vitamin B12 deficiency occur. Findings from several studies have indicated that vitamin B12 may be a possible treatment for pain in fibromyalgia. The aim of the proposed study is to evaluate whether vitamin B12 decreases pain sensitivity and the experience of pain (ie, hyperalgesia and allodynia) in women with fibromyalgia.

METHODS AND ANALYSIS

The study is a randomised, placebo-controlled, single-blind, clinical trial with two parallel groups which are administered mecobalamin (vitamin B12) or placebo over 12 weeks. 40 Swedish women aged 20-70 years with an earlier recorded diagnosis of fibromyalgia are randomised into the placebo group or the treatment group, each consisting of 20 participants. Outcomes consist of questionnaires measured at baseline and after 12 weeks of treatment. A final re-evaluation will then follow 12 weeks after treatment ends. The primary outcome is tolerance time, maximised to 3 min, which is assessed using the cold pressor test. In order to broaden the understanding of the lived experience of participants, qualitative interviews will be conducted using a phenomenological approach on a lifeworld theoretical basis (reflective lifeworld research approach).

ETHICS AND DISSEMINATION

The protocol for the study is approved by the local ethical committee at Linkoping (EPM; 2018/294-31, appendices 2019-00347 and 2020-04482). The principles of the Helsinki Declaration are followed regarding oral and written consent to participate, confidentiality and the possibility to withdraw participation from the study at any time. The results will primarily be communicated through peer-reviewed journals and conferences.

TRIAL REGISTRATION NUMBER

NCT05008042.

Sex and gender differences in pain

Chronic pain affects 20% of adults and is one of the leading causes of disability worldwide. Women and girls are disproportionally affected by chronic pain. About half of chronic pain conditions are more common in women, with only 20% having a higher prevalence in men. There are also sex and gender differences in acute pain sensitivity. Pain is a subjective experience made up of sensory, cognitive, and emotional components. Consequently, there are multiple dimensions through which sex and gender can influence the pain experience. Historically, most preclinical pain research was conducted exclusively in male animals. However, recent studies that included females have revealed significant sex differences in the physiological mechanisms underlying pain, including sex specific involvement of different genes and proteins as well as distinct interactions between hormones and the immune system that influence the transmission of pain signals. Human neuroimaging has revealed sex and gender differences in the neural circuitry associated with pain, including sex specific brain alterations in chronic pain conditions. Clinical pain research suggests that gender can affect how an individual contextualizes and copes with pain. Gender may also influence the susceptibility to develop chronic pain. Sex and gender biases can impact how pain is perceived and treated clinically. Furthermore, the efficacy and side effects associated with different pain treatments can vary according to sex and gender. Therefore, preclinical and clinical research must include sex and gender analyses to understand basic mechanisms of pain and its relief, and to develop personalized pain treatment.

Can fibromyalgia be considered a characteristic symptom of climacterium?

Fibromyalgia syndrome (FMS) is a chronic pain syndrome, characterised by diffuse pain in musculoskeletal system and accompanied by stiffness, fatigue, tender points, sleep disturbances and cognitive and gastrointestinal symptoms. It affects middle-aged women (between 40 and 65) predominantly. Climacteric syndrome, which is characterised by vasomotor, somatic (headache, sleep disorders, myalgia and arthralgia) and psychical (mood changes) symptoms, results from the change in brain neurotransmitter concentrations due to gradual decline of ovarian hormone levels. Currently, studies focus on the similarities of FMS and climacteric syndrome in terms of age of occurrence, epidemiology, etiopathogenesis, symptomatology and treatment. Hormonal fluctuation during menopausal transition is likely the triggering factor for both syndromes. Therefore, hormone replacement therapy is a favourable approach in the treatment of FMS due to the antiallodynic, anti-inflammatory and neuroprotective effect of oestrogen. In this review, we emphasise the similarity of FMS and climacteric syndrome and suggested that FMS could be considered as a characteristic symptom of climacterium.

Involvement of glutamate receptors of the paragigantocellularis lateralis nucleus in the pain modulatory effect of 17β-estradiol in male rats

The pain modulatory role of the paragigantocellularis lateralis nucleus (LPGi) and the 17β-estradiol has thoroughly been probed. This study investigates the contribution of ionotropic glutamate receptors in pain modulatory effect of intra-LPGi injection of 17β-estradiol. For this purpose, the LPGi nucleus cannulation was performed and drugs were injected into this nucleus, 15 min prior to the formalin test. The duration of formalin-induced flexing and licking behaviors was recorded for 60 min immediately after formalin injection. The results showed that the flexing behavior is significantly decreased by intra-LPGi injection of 0.8 µmol 17β-estradiol duringboth phases of formalin test (P < 0.001). However, 17β-estradiol attenuated the licking duration only in the second phase (P < 0.001). Interestingly, NMDA and AMPA/kainate receptor antagonists (AP5 and CNQX, respectively) significantly counteracted the analgesic effect of intra-LPGi injection of 17β-estradiol in both phases of the formalin test (P < 0.001). Consequently, the revealing results showed that the analgesic effect of intra-LPGi injection of 17β-estradiol on acute inflammatory pain might be mediated via the activation of ionotropic glutamate receptors.

The Importance of G-protein Coupled Estrogen Receptor in Patients With Fibromyalgia

Objectives

This study aims to analyze the G-protein coupled estrogen receptor (GPER/GPR30) activity in patients with fibromyalgia syndrome (FMS).

Patients and methods

We enrolled 40 female patients with FMS (mean age 42.9±11.2 years; range, 18 to 64 years) diagnosed according to the 2010 American College of Rheumatology classification criteria and 30 age- and body mass index-matched female healthy controls (mean age 43.7±13.6 years; range, 19 to 64 years). Sex hormones of patients (morning) including estradiol, follicle stimulating hormone, luteinizing hormone, and prolactin (PRL) were recorded. FMS severity was assessed by Fibromyalgia Impact Questionnaire (FIQ). Serum GPER levels were measured by using a quantitative sandwich enzyme-linked immunosorbent assay method with a commercial kit.

Results

G-protein coupled estrogen receptor levels were 0.11 (0.02-0.9) ng/mL in the FMS patients and 0.059 (0.01-0.13) ng/mL in controls, with a statistically significant difference (p=0.037). GPER levels were positively correlated with age and negatively correlated with PRL, while they were not correlated with FIQ. Differential diagnosis for FMS with receiver operating characteristic (ROC) analysis for the serum GPER levels was statistically significant (area under the ROC curve: 0.653, confidence interval: 0.522-0.785, p=0.029). High values indicated FMS, with a threshold of >0.075, sensitivity of 60%, and specificity of 60%.

Conclusion

The GPER levels of FMS patients were higher than those of the controls. Thus, GPER levels may be considered as a biomarker in the diagnosis of FMS independent of disease severity.

Sex differences and estradiol involvement in hyperalgesia and allodynia in an experimental model of fibromyalgia

Fibromyalgia (FM) is a musculoskeletal chronic pain syndrome. Its prevalence in women is higher than in men possibly by hormonal factors given that symptoms are aggravated during sex hormone-related events, such as the premenstrual period, pregnancy, postpartum or menopause. The aim of the present study was to investigate whether hyperalgesia and allodynia, in reserpine-induced experimental FM, depend on sex, estrous cycle, ovariectomy and replacement with 17β-estradiol. To fulfill this objective, we compared males, intact females with known estrous cycle phases and ovariectomized (OVX) rats treated with 17β-estradiol. Data demonstrated that reserpine administration disrupted the normal estrous cycle and produced that all females entered metestrus/diestrus. In addition, this treatment leads to muscle hyperalgesia and tactile allodynia in a similar manner in male and intact female rats. However, the absence of ovarian hormones (in OVX rats) increased muscle nociception. 17β-estradiol (2.5-10μg/rat) produced antihyperalgesic and antiallodynic effects 24h, but not 8h, after its administration, suggesting a genomic mechanism. The present results support the validity of the reserpine-induced FM model for searching alternatives of treatment, particularly during endocrine phases when pain is exacerbated such as menopause, and that 17β-estradiol replacement might be useful.

Ambroxol for the treatment of fibromyalgia: science or fiction?

Fibromyalgia appears to present in subgroups with regard to biological pain induction, with primarily inflammatory, neuropathic/neurodegenerative, sympathetic, oxidative, nitrosative, or muscular factors and/or central sensitization. Recent research has also discussed glial activation or interrupted dopaminergic neurotransmission, as well as increased skin mast cells and mitochondrial dysfunction. Therapy is difficult, and the treatment options used so far mostly just have the potential to address only one of these aspects. As ambroxol addresses all of them in a single substance and furthermore also reduces visceral hypersensitivity, in fibromyalgia existing as irritable bowel syndrome or chronic bladder pain, it should be systematically investigated for this purpose. Encouraged by first clinical observations of two working groups using topical or oral ambroxol for fibromyalgia treatments, the present paper outlines the scientific argument for this approach by looking at each of the aforementioned aspects of this complex disease and summarizes putative modes of action of ambroxol. Nevertheless, at this point the evidence basis for ambroxol is not strong enough for clinical recommendation.

Pain Severity in Relation to the Final Menstrual Period in a Prospective Multiethnic Observational Cohort: Results From the Study of Women's Health Across the Nation

The development of pain is common in midlife, resulting in increased health care utilization and costs. The aim of this study was to determine the longitudinal trajectory of overall bodily pain among women during the transition between the reproductive years and menopause. We conducted analyses on a community-based, longitudinal cohort of women enrolled in the Study of Women's Health Across the Nation. One thousand four hundred ninety-five women met inclusion criteria, including: 1) defined date of the final menstrual period (FMP), and 2) complete data on Short Form-36 bodily pain. The primary exposure was time to/from the FMP. The primary outcome was the rate of change in Short Form-36 bodily pain, measured on a scale of 0 to 100 with 100 being the most severe pain. We performed within-person trajectory analyses using piecewise regression following nonparametric modeling of functional forms. Mean bodily pain score at the time of the FMP was 29. Mean bodily pain increased at a rate of .26 per year during the transmenopause (the interval spanning 4.5 years before the FMP through .5 years after the FMP), and decreased at a rate of .23 per year after that. Depression and sleep problems were associated with greater increases in pain during the late reproductive years, whereas abdominal cramps at baseline predicted greater decreases in pain during the late reproductive years.

PERSPECTIVE

This article shows that bodily pain increases during the transmenopause and then diminishes during postmenopause. These differences may reflect differences in underlying mechanisms of pain in the 2 periods. Although mean changes were small and unlikely to be clinically meaningful, the magnitude of change varied across subgroups of women.

Sex differences and hormonal modulation of deep tissue pain

Women disproportionately suffer from many deep tissue pain conditions. Experimental studies show that women have lower pain thresholds, higher pain ratings and less tolerance to a range of painful stimuli. Most clinical and epidemiological reports suggest female gonadal hormones modulate pain for some, but not all, conditions. Similarly, animal studies support greater nociceptive sensitivity in females in many deep tissue pain models. Gonadal hormones modulate responses in primary afferents, dorsal horn neurons and supraspinal sites, but the direction of modulation is variable. This review will examine sex differences in deep tissue pain in humans and animals focusing on the role of gonadal hormones (mainly estradiol) as an underlying component of the modulation of pain sensitivity.

Estrogenic influences in pain processing

Gonadal hormones not only play a pivotal role in reproductive behavior and sexual differentiation, they also contribute to thermoregulation, feeding, memory, neuronal survival, and the perception of somatosensory stimuli. Numerous studies on both animals and human subjects have also demonstrated the potential effects of gonadal hormones, such as estrogens, on pain transmission. These effects most likely involve multiple neuroanatomical circuits as well as diverse neurochemical systems and they therefore need to be evaluated specifically to determine the localization and intrinsic characteristics of the neurons engaged. The aim of this review is to summarize the morphological as well as biochemical evidence in support for gonadal hormone modulation of nociceptive processing, with particular focus on estrogens and spinal cord mechanisms.

Hormone therapy for sexual function in perimenopausal and postmenopausal women

BACKGROUND

The perimenopausal and postmenopausal periods are associated with many symptoms, including sexual complaints.

OBJECTIVES

To assess the effect of hormone therapy (HT) on sexual function in perimenopausal and postmenopausal women.

SEARCH METHODS

We searched for articles in the Cochrane Menstrual Disorders and Subfertility Group (MDSG) Specialised Register, CENTRAL, MEDLINE, EMBASE, CINAHL, PsycINFO, LILACS, ClinicalTrials.gov, Current Controlled Trials, WHO International Clinical Trials Registry Platform, ISI Web of Knowledge and OpenGrey. The last search was performed in December 2012.

SELECTION CRITERIA

We included randomised controlled trials comparing HT to either placebo or no intervention (control). We considered as HT estrogens alone; estrogens in combination with progestogens; synthetic steroids (for example tibolone); or selective estrogen receptor modulators (SERMs) (for example raloxifene, bazedoxifene). Studies of other drugs possibly used in the relief of menopausal symptoms were excluded. We included studies that evaluated sexual function using any validated assessment tool. The primary outcome was a composite score for sexual function and the scores for individual domains (arousal and sexual interest, orgasm, and pain) were secondary outcomes. Studies were selected by two authors independently.

DATA COLLECTION AND ANALYSIS

Data were independently extracted by two authors and checked by a third. Risk of bias assessment was performed independently by two authors. We contacted study investigators as required. Data were analysed using standardized mean difference (SMD) and relative risk (RR). We stratified the analysis by participant characteristics with regard to menopausal symptoms. The overall quality of the evidence for the primary outcome was evaluated using the GRADE criteria.

MAIN RESULTS

The search retrieved 2351 records from which 27 studies (16,393 women) were included. The 'symptomatic or early post-menopausal' subgroup included nine studies: perimenopausal women (one study), up to 36 months postmenopause (one study), up to five years postmenopause (one study), experiencing vasomotor or other menopausal symptoms (five studies), or experiencing hot flushes and sexual dysfunction (one study). The 'unselected postmenopausal women' subgroup included 18 studies, which included women regardless of menopausal symptoms and permitted the inclusion of women with more than five years since the final menstrual period. No studies were restricted to women with sexual dysfunction. Only five studies evaluated sexual function as a primary outcome. Eighteen studies were deemed at high risk of bias, and the other nine studies were at unclear risk of bias. Twenty studies received commercial funding.Findings for sexual function (measured by composite score):For estrogens alone versus control, in symptomatic or early postmenopausal women the SMD and 95% CI were compatible with a small to moderate benefit in sexual function for the HT group (SMD 0.38, 95% CI 0.23 to 0.54, P < 0.00001, 3 studies, 699 women, I² = 55%, high-quality evidence). In unselected postmenopausal women, the 95% CI was compatible with no effect to a small benefit (SMD 0.16, 95% CI -0.02 to 0.34, P = 0.08, 2 studies, 478 women, I² = 44%, low-quality evidence). The subgroups were not pooled because of considerable heterogeneity.For estrogens combined with progestogens versus control, in symptomatic or early postmenopausal women the 95% CI was compatible with a small to moderate benefit for sexual function in the HT group (SMD 0.42, 95% CI 0.19 to 0.64, P = 0.0003, 1 study, 335 women, moderate-quality evidence). In unselected postmenopausal women, the 95% CI was compatible with no effect to a small benefit (SMD 0.09, 95% CI -0.02 to 0.20, P = 0.10, 3 studies, 1314 women, I² = 0%, moderate-quality evidence). The subgroups were not pooled because of considerable heterogeneity.For tibolone versus control, in symptomatic or early postmenopausal women the 95% CI was compatible with no effect to a small benefit for sexual function in the HT group (SMD 0.13, 95% CI 0.00 to 0.26, P = 0.05, 1 study, 883 women, low-quality evidence). In unselected postmenopausal women, the 95% CI was compatible with no effect to a moderate benefit (SMD 0.38, 95% CI 0.04 to 0.71, P = 0.03, 2 studies, 142 women, I² = 0%, low-quality evidence). In the combined analysis, the 95% CI was compatible with no effect to a small benefit (SMD 0.17, 95% CI 0.04 to 0.29, P = 0.008, 3 studies, 1025 women, I² = 20%).For SERMs versus control, in symptomatic or early postmenopausal women the 95% CI was compatible with no effect to a moderate benefit for sexual function in the HT group (SMD 0.23, 95% CI -0.04 to 0.50, P = 0.09, 1 study, 215 women, low-quality evidence). In unselected postmenopausal women, the 95% CI was compatible with small harm to a small benefit (SMD 0.04, 95% CI -0.20 to 0.29, P = 0.72, 1 study, 283 women, low-quality evidence). In the combined analysis, the 95% CI was compatible with no effect to a small benefit (SMD 0.13, 95% CI -0.05 to 0.31, P = 0.16, 2 studies, 498 women, I² = 2%).A comparison of SERMs combined with estrogens versus control was only evaluated in symptomatic or early postmenopausal women. The 95% CI was compatible with no effect to a small benefit for sexual function in the HT group (SMD 0.21, 95% CI 0.00 to 0.43, P = 0.05, 1 study, 542 women, moderate-quality evidence).

AUTHORS' CONCLUSIONS

HT treatment with estrogens alone or in combination with progestogens was associated with a small to moderate improvement in sexual function, particularly in pain, when used in women with menopausal symptoms or in early postmenopause (within five years of amenorrhoea), but not in unselected postmenopausal women. Evidence regarding other HTs (synthetic steroids and SERMs) is of low quality and we are uncertain of their effect on sexual function. The current evidence does not suggest an important effect of tibolone or of SERMs alone or combined with estrogens on sexual function. More studies evaluating the effect of synthetic steroids, SERMS and the association of SERM + estrogens would improve the quality of the evidence for the effect of these treatments on sexual function in peri and postmenopausal women. Future studies should also evaluate the effect of HT solely among women with sexual complaints.

Importance of sex to pain and its amelioration; relevance of spinal estrogens and its membrane receptors

Estrogens have a multitude of effects on opioid systems and are thought to play a key role in sexually dimorphic nociception and opioid antinociception. Heretofore, classical genomic actions of estrogens are largely thought to be responsible for the effects of these steroids on nociception and opioid antinociception. The recent discovery that estrogens can also activate estrogen receptors that are located in the plasma membrane, the effects of which are manifest in seconds to minutes instead of hours to days has revolutionized our thinking concerning the ways in which estrogens are likely to modulate pain responsiveness and the dynamic nature of that modulation. This review summarizes parameters of opioid functionality and nociception that are subject to modulation by estrogens, underscoring the added dimensions of such modulation that accrues from rapid membrane estrogen receptor signaling. Implications of this mode of signaling regarding putative sources of estrogens and its degradation are also discussed.

Influence of estrogen levels on thermal perception, pain thresholds, and pain tolerance: studies on women undergoing in vitro fertilization

We examined the relationship between estrogen and pain in women undergoing in vitro fertilization (IVF). Quantitative sensory tests (QST) were performed twice during the IVF-regimen: once during hormonal down-regulation and once during hormonal up-regulation. A group of healthy men and a group of women using monophasic contraceptives were also examined, to control for session-to-session effects. Among the women undergoing IVF, serum 17β-estradiol levels differed strongly between treatments as expected, and increased from 65.7 (SD = 26) pmol/L during the down-regulation phase, to 5,188 (SD = 2,524) pmol/L during the up-regulation phase. Significant outcomes in the QST were only seen for temperature perception thresholds (1.7 °C versus 2.2 °C; P = .003) and cold pain threshold (11.5 °C versus 14.5 °C; P = .04). A similar change in cold pain threshold was also seen in the 2 control groups, however, and statistical analysis suggested that this change was due to a session-to-session effect rather than being the result of hormonal modulation. Heat pain thresholds, heat tolerance, pressure pain thresholds, and the cold pressor test showed no significant differences between sessions. These data demonstrate that pain perception and pain thresholds in healthy women show little, if any, changes even with major variations in serum estradiol levels.

PERSPECTIVE

This study shows that pain perception and tolerance in women undergoing in vitro fertilization do not vary, despite the dramatic changes in 17β-estradiol levels induced by the treatment regimen. The result thus suggests that in humans, contrary to experimental animals, changes in estrogen levels have little influence on pain sensitivity.