Association of brown adipose tissue activity with circulating sex hormones and fibroblast growth factor 21 in the follicular and luteal phases in young women.

BACKGROUND: Thermogenesis is influenced by fluctuations in sex hormones during the menstrual cycle in premenopausal women. The thermogenic activity and mass of brown adipose tissue (BAT) are regulated by endocrine factors, including sex hormones and fibroblast growth factor 21 (FGF21). However, the relationship between human BAT and these endocrine fluctuations within individuals remains to be elucidated. This study aimed to assess variations in BAT activity between the luteal and follicular phases and identify correlations with circulating levels of sex hormones and FGF21. METHODS: Healthy young women were enrolled in an observational study. Measurement of BAT activity and blood analyses were performed in both the follicular and luteal phases. BAT activity was analyzed using thermography with 2-h cold exposure. Plasma 17ß-estradiol, progesterone, and FGF21 levels were determined by enzyme-linked immunosorbent assay. A comparative analysis within individuals was conducted in 13 women to compare the follicular and luteal phases. Furthermore, sensitivity analysis was carried out in 21 women during the follicular phase only. RESULTS: Plasma 17ß-estradiol and progesterone levels were significantly higher in the luteal phase, whereas plasma FGF21 level was significantly higher in the follicular phase. Comparison analysis found no significant differences in cold-induced BAT activity between the follicular and luteal phases in young women. Correlation analysis in both comparison and sensitivity analyses found that plasma 17ß-estradiol and progesterone levels were not associated with BAT activity, whereas plasma FGF21 levels were significantly and positively correlated with BAT activity only in the follicular phase. In addition, plasma 17ß-estradiol levels in the follicular phase were significantly and positively associated with plasma FGF21 levels in both the comparison and sensitivity analyses. CONCLUSIONS: The thermogenic activity of BAT during cold exposure was comparable between the follicular and luteal phases in young women. Higher BAT activity was associated with elevated levels of plasma FGF21 only in the follicular phase, which is related to increased plasma 17ß-estradiol levels.

Comparing the outcomes of in-vitro fertilization in patients receiving vaginal, subcutaneous, and intramuscular progesterone for luteal phase support: a three-armed randomized controlled trial.

BACKGROUND: The optimal approach to luteal-phase support in infertility treatment remains a subject of debate. This study was conducted to investigate the clinical outcomes, side effects, and patient satisfaction associated with vaginal, subcutaneous, and intramuscular progesterone administration in infertile women undergoing Frozen Embryo Transfer (FET). METHODS: This three-armed randomized clinical trial assigned infertile patients eligible for FET to three progesterone treatment groups: vaginal suppositories (400 mg twice daily; n = 100), subcutaneous injections (25 mg daily; n = 102), and intramuscular injections (50 mg daily; n = 108). The primary outcomes were chemical and clinical pregnancy rates per embryo transfer cycle, with chemical pregnancy defined as beta-human chorionic gonadotropin levels > 50 IU/mL two weeks post-transfer and clinical pregnancy confirmed by ultrasound four weeks later. Exploratory outcomes included progesterone-related adverse effects and participant satisfaction, assessed via a Likert-scale survey 12 weeks post-transfer. Statistical analyses included Chi-square tests for categorical data, one-way analysis of variances, and Kruskal-Wallis tests for continuous data. RESULTS: The intramuscular progesterone group had significantly higher chemical pregnancy rates compared to the vaginal and subcutaneous groups (41.7% vs. 26.0% and 27.5%, respectively; p = 0.026). Although the clinical pregnancy rate was also higher in the intramuscular group (32.4%) compared to the vaginal (23.0%) and subcutaneous groups (21.6%), this difference was not statistically significant (p = 0.148). Additionally, patient satisfaction was greater with vaginal and subcutaneous applications than with intramuscular injections (p < 0.001), likely due to a significantly higher incidence of side effects, such as pain and edema at the injection site, in the intramuscular group (p < 0.001). CONCLUSIONS: We found that intramuscular progesterone resulted in higher chemical pregnancy rates than vaginal or subcutaneous routes, but this did not translate into higher clinical pregnancy rates. Despite its effectiveness, intramuscular administration was associated with more adverse effects and lower patient satisfaction. Future research should explore optimizing progesterone regimens to balance efficacy and patient comfort. TRIAL REGISTRATION: The trial protocol was registered on December 6, 2020, in the Iranian Registry of Clinical Trials (IRCT), a primary registry in the World Health Organization (WHO) Registry Network, under the registration number IRCT20141217020351N12.

Influence of Menstrual Phase and Symptoms on Match Running in Professional Footballers.

This study examined the effects of menstrual cycle phases and symptoms on match running performance in football (soccer) players. Twenty-one nonhormonal contraceptive using football players from four professional teams were monitored for up to four menstrual cycles during a domestic league season. Menstrual phases, classified as early-follicular phase (EFP), mid-late follicular phase (MFP), and luteal phase (LP), were determined by self-reporting of menstruation and urinary hormone tests (luteinizing hormone and pregnanediol-3-glucuronide). On match day, players completed a menstrual symptom severity questionnaire. In repeated matches, players wore 10 Hz Global Positioning Satellite (GPS) devices to measure relative (/min) total distance, high-speed running distance, very high-speed distance, peak speed, acceleration count, and deceleration count. Linear mixed models were performed for each GPS measure to determine the relationship with phase or symptoms. Data for 7 and 10 players were included for menstrual phase and menstrual symptoms analyses, respectively. A significantly higher total distance was reported during MFP compared to EFP (Δ 5.1 m min-1; p = 0.04) and LP (Δ 5.8 m min-1; p = 0.007). Significantly greater high-speed running was reported during MFP compared to EFP (Δ 1.2 m min-1; p = 0.012) and LP (Δ 1.1 m min-1; p = 0.007). No significant effect of menstrual phase was found for any other GPS measures (p > 0.05). Accelerations declined with increasing symptom severity (p = 0.021, estimate = -0.01count.min-1). Menstrual symptom severity did not affect any other GPS measures (p > 0.05). In conclusion, greater total distance and high-speed running occurred during the MFP. Additionally, accelerations minimally decreased with increasing menstrual symptom severity. Large intra- and inter-variability existed, suggesting individualized monitoring and management of menstrual effects on performance would be beneficial.

Emotion and birth control: Emotion regulation ERPs differ based on menstrual cycle phase and hormonal contraceptive use.

While hormonal contraceptives (HCs) like oral contraceptive pills (OCs) and intrauterine devices (IUDs) can reportedly influence mood, the evidence is mixed, and the mechanisms remain unclear. Emotion reactivity and regulation processes may be hormone-sensitive and underlie these mood changes. This study sought to investigate the role of the menstrual cycle and HC use in emotion regulation using ERP measures during an emotion regulation paradigm. Participants with a natural cycle (NC) were measured in the mid-follicular and mid-luteal phase (within-subject design, n = 26), and compared with OC (n = 36) and IUD (n = 25) users. The centroparietal late positive potential (LPP) reflected negative emotion reactivity and its modulation by cognitive reappraisal served as a marker for emotion regulation processing. NC participants had a lower LPP amplitude in the mid-luteal compared to the mid-follicular phase. Reactivity to negative emotional stimuli decreased over time in the mid-luteal phase, whereas the HC groups showed sustained LPP activation. Reappraisal led only to significant LPP changes in the mid-follicular phase, and not in the mid-luteal phase or HC groups. Our results showed a specific left frontal activity (FR-LPP) in the contrast that reflected emotion regulation processing. This activity was highest in the mid-follicular phase, and was significantly different from the OC users but not from the IUD group. Higher self-reported PMS symptoms were associated with stronger effects on the reduced mid-luteal LPP activity and with lower FR-LPP amplitude in the mid-follicular phase. No effect of OC phase (active pill use versus pill pause) was found. These findings add insights into the neurophysiological underpinnings of hormone-related mood changes and demonstrate the importance of considering hormonal status and PMS symptoms in emotion research.

Performance of the MiniMed 780G system on mitigating menstrual cycle-dependent glycaemic variability.

AIM: To map the glycaemic variabilities and insulin requirements across different phases of the menstrual cycle and assess the efficacy and performance of the MiniMed 780G system on mitigating glycaemic variabilities during phases of the menstrual cycle. MATERIALS AND METHODS: A pilot study recruiting 15 adolescent and young adult females with type 1 diabetes was conducted. Only females with regular spontaneous menstruation were enrolled in the current study. Phases of each menstrual cycle were determined as either follicular phase or luteal phase. The study analysed continuous glucose monitoring metrics during two study periods: the open loop period (OLP) and the advanced hybrid closed-loop (AHCL) period; each period lasted 3 consecutive months. RESULTS: During the OLP, the mean time in range (TIR) significantly decreased during the luteal phase compared with the follicular phase (65.13% ± 3.07% vs. 70.73% ± 2.05%) (P < .01). The mean time above range significantly increased from 21.07% ± 2.58% during the follicular phase to 24.87% ± 2.97% during the luteal phase (P < .01). After initiating the AHCL period, TIR was comparable during both phases of the menstrual cycle (P = .72), without increasing the time spent below 70 mg/dL (P > .05). Regarding insulin delivery during the AHCL period, the percentage of Auto basal and Auto correction delivered by the algorithm increased by 13.55% and 30.6%, respectively (P < .01), during the luteal phase. CONCLUSIONS: The fully automated adaptive algorithm of the MiniMed 780G system mitigated menstrual cycle-dependent glycaemic variability, successfully attaining the recommended glycaemic outcomes with a TIR greater than 70% throughout the entire menstrual cycle.

Effect of estradiol supplementation on luteal support following a significant reduction in serum estradiol levels after hCG triggering: a prospective randomized controlled trial.

OBJECTIVE: This study aimed to evaluate the impact of adding 4 mg estradiol valerate to progesterone for luteal support on pregnancy rates in IVF cycles following a long protocol with reduced luteal serum estradiol levels post-hCG triggering. DESIGN, SETTING, AND PARTICIPANTS: The prospective randomized controlled trial was conducted at a public tertiary hospital reproductive center with 241 patients who experienced a significant decrease in serum estrogen levels post-oocyte retrieval. INTERVENTIONS: Participants received either a daily 4 mg dose of estradiol valerate in addition to standard progesterone or standard progesterone alone for luteal support. RESULTS: The ongoing pregnancy rate did not show a significant difference between the E2 group and the control group (56.6% vs. 52.2%, with an absolute rate difference (RD) of 4.4%, 95% CI -0.087 to 0.179, P = 0.262). Similarly, the live birth rate, implantation rate, clinical pregnancy rate, early abortion rate, and severe OHSS rate were comparable between the two groups. Notably, the E2 group had no biochemical miscarriages, contrasting significantly with the control group (0.0% vs. 10.7%, RD -10.7%, 95% CI -0.178 to -0.041, P = 0.000). In the blastocyst stage category, the clinical pregnancy rate was notably higher in the E2 group compared to the control group (75.6% vs. 60.8%, RD 14.9%, 95% CI 0.012 to 0.294, P = 0.016). CONCLUSION: Adding 4 mg estradiol valerate to progesterone for luteal support does not affect the ongoing pregnancy rate in embryo transfer cycles using a long protocol with a significant decrease in serum estradiol levels after hCG triggering. However, it may reduce biochemical miscarriages and positively impact clinical pregnancy rates in blastocyst embryo transfer cycles. TRIAL REGISTRATION: ChiCTR1800020342.

Associations of luteal phase changes in vagally mediated heart rate variability with premenstrual emotional changes.

BACKGROUND: A recent meta-analysis revealed that vagally mediated heart rate variability (vmHRV; a biomarker of emotion regulation capacity) significantly decreases in the luteal phase of the menstrual cycle. As two follow-up studies suggest, these vmHRV decreases are driven primarily by increased luteal progesterone (P4). However, analyses also revealed significant interindividual differences in vmHRV reactivity to the cycle, which is in line with longstanding evidence for interindividual differences in mood sensitivity to the cycle. The present study begins to investigate whether these interindividual differences in vmHRV cyclicity can explain who is at higher risk of showing premenstrual emotional changes. We expected a greater degree of midluteal vmHRV decrease to be predictive of a greater premenstrual increase in negative affect. METHODS: We conducted an observational study with a naturally cycling community sample (N = 31, M = 26.03 years). Over a span of six weeks, participants completed (a) daily ratings of negative affect and (b) counterbalanced lab visits in their ovulatory, midluteal, and perimenstrual phases. Lab visits were scheduled based on positive ovulation tests and included assessments of baseline vmHRV and salivary ovarian steroid levels. RESULTS: In line with previous research, multilevel models suggest that most of the sample shows ovulatory-to-midluteal vmHRV decreases which, however, were not associated with premenstrual emotional changes. Interestingly, it was only the subgroup with luteal increases in vmHRV whose negative affect markedly worsened premenstrually and improved postmenstrually. CONCLUSION: The present study begins to investigate cyclical changes in vmHRV as a potential biomarker of mood sensitivity to the menstrual cycle. The results demonstrate a higher level of complexity in these associations than initially expected, given that only atypical midluteal increases in vmHRV are associated with greater premenstrual negative affect. Potential underlying mechanisms are discussed, among those the possibility that luteal vmHRV increases index compensatory efforts to regulate emotion in those with greater premenstrual negative affect. However, future studies with larger and clinical samples and more granular vmHRV assessments should build on these findings and further explore associations between vmHRV cyclicity and menstrually related mood changes.

Use of hCG for luteal support in natural frozen-thawed blastocyst transfer cycles: a cohort study.

Introduction: In the realm of natural frozen-thawed embryo transfer (FET) cycles, the application of luteal phase support (LPS) is a prevalent practice, primarily due to its beneficial impact on reproductive outcomes. Among the various LPS medications, human chorionic gonadotropin (hCG) is one that exerts its function on both the corpus luteum and the endometrium. Objective: To evaluate the effect of hCG administration as LPS on reproductive outcomes in natural FET cycles. Methods: This study was a retrospective cohort analysis conducted at a tertiary care hospital. It included women who underwent natural FET treatment from January 2018 to December 2022. Participants were divided into the hCG LPS group and the non-hCG LPS group on the basis of whether they used hCG as LPS after blastocyst transfer. The primary outcome was the clinical pregnancy and live birth rates. The secondary outcomes included the early miscarriage rate (before 12th gestational week) and total miscarriage rate. Results: A total of 4762 women were included in the analysis, and 1910 received hCG LPS and 2852 received no hCG LPS (control group). In the general cohort, the clinical pregnancy and live birth rates in the hCG LPS group were significantly lower than those in the control group (63.82% vs 66.41%, aOR 0.872, 95% CI 0.765-0.996, P=0.046; 53.98% vs 57.15%, aOR 0.873, 95% CI 0.766-0.991, P=0.035, respectively). The early miscarriage and total miscarriage rates were similar between the two groups. In a subgroup analysis, in women who received an hCG trigger, there was no significant difference in the clinical pregnancy rate or live birth rate between the two groups. However, in women who ovulated spontaneously, the clinical pregnancy and live birth rates in the hCG LPS group were significantly lower than those in the control group (60.99% vs 67.21%, aOR 0.786, 95% CI 0.652-0.946, P=0.011; 50.56% vs 57.63%, aOR 0.743, 95% CI 0.619-0.878, P=0.001, respectively). Conclusion: Among women undergoing natural cycle frozen-thawed blastocyst transfer, hCG LPS is associated with lower clinical pregnancy and live birth rates. Additionally, the adverse effect of hCG LPS is more pronounced in women who ovulate spontaneously.

Selective serotonin reuptake inhibitors for premenstrual syndrome and premenstrual dysphoric disorder.

BACKGROUND: Premenstrual syndrome (PMS) is a combination of physical, psychological and social symptoms in women of reproductive age, and premenstrual dysphoric disorder (PMDD) is a severe type of the syndrome, previously known as late luteal phase dysphoric disorder (LLPDD). Both syndromes cause symptoms during the two weeks leading up to menstruation (the luteal phase). Selective serotonin reuptake inhibitors (SSRIs) are increasingly used as a treatment for PMS and PMDD, either administered in the luteal phase or continuously. We undertook a systematic review to assess the evidence of the positive effects and the harms of SSRIs in the management of PMS and PMDD. OBJECTIVES: To evaluate the benefits and harms of SSRIs in treating women diagnosed with PMS and PMDD. SEARCH METHODS: We searched the Cochrane Gynaecology and Fertility (CGF) Specialised Register of Controlled Trials, CENTRAL, MEDLINE, Embase and PsycINFO for randomised controlled trials (RCTs) in November 2023. We checked reference lists of relevant studies, searched trial registers and contacted experts in the field for any additional trials. This is an update of a review last published in 2013. SELECTION CRITERIA: We considered studies in which women with a prospective diagnosis of PMS, PMDD or LLPDD were randomised to receive SSRIs or placebo. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. We pooled data using a random-effects model. We calculated standardised mean differences (SMDs) with 95% confidence intervals (CIs) for premenstrual symptom scores, using 'post-treatment' scores for continuous data. We calculated odds ratios (ORs) with 95% CIs for dichotomous outcomes. We stratified analyses by type of administration (luteal phase or continuous). We calculated absolute risks and the number of women who would need to be taking SSRIs in order to cause one additional adverse event (i.e. the number needed to treat for an additional harmful outcome (NNTH)). We rated the overall certainty of the evidence for the main findings using GRADE. MAIN RESULTS: We included 34 RCTs in the review. The studies compared SSRIs (i.e. fluoxetine, paroxetine, sertraline, escitalopram and citalopram) to placebo. SSRIs probably reduce overall self-rated premenstrual symptoms in women with PMS and PMDD (SMD -0.57, 95% CI -0.72 to -0.42; I2 = 51%; 12 studies, 1742 participants; moderate-certainty evidence). SSRI treatment was probably more effective when administered continuously than when administered only in the luteal phase (P = 0.03 for subgroup difference; luteal phase group: SMD -0.39, 95% CI -0.58 to -0.21; 6 studies, 687 participants; moderate-certainty evidence; continuous group: SMD -0.69, 95% CI -0.88 to -0.51; 7 studies, 1055 participants; moderate-certainty evidence). The adverse effects associated with SSRIs were nausea (OR 3.30, 95% CI 2.58 to 4.21; I2 = 0%; 18 studies, 3664 women), insomnia (OR 1.99, 95% CI 1.51 to 2.63; I2 = 0%; 18 studies, 3722 women), sexual dysfunction or decreased libido (OR 2.32, 95% CI 1.57 to 3.42; I2 = 0%; 14 studies, 2781 women), fatigue or sedation (OR 1.52, 95% CI 1.05 to 2.20; I2 = 0%; 10 studies, 1230 women), dizziness or vertigo (OR 1.96, 95% CI 1.36 to 2.83; I2 = 0%; 13 studies, 2633 women), tremor (OR 5.38, 95% CI 2.20 to 13.16; I2 = 0%; 4 studies, 1352 women), somnolence and decreased concentration (OR 3.26, 95% CI 2.01 to 5.30; I2 = 0%; 8 studies, 2050 women), sweating (OR 2.17, 95% CI 1.36 to 3.47; I2 = 0%; 10 studies, 2304 women), dry mouth (OR 2.70, 95% CI 1.75 to 4.17; I2 = 0%; 11 studies, 1753 women), asthenia or decreased energy (OR 3.28, 95% CI 2.16 to 4.98; I2 = 0%; 7 studies, 1704 women), diarrhoea (OR 2.06, 95% CI 1.37 to 3.08; I2 = 0%; 12 studies, 2681 women), and constipation (OR 2.39, 95% CI 1.09 to 5.26; I2 = 0%; 7 studies, 1022 women). There was moderate-certainty evidence for all adverse effects other than somnolence/decreased concentration, which was low-certainty evidence. Overall, the certainty of the evidence was moderate. The main weakness was poor reporting of study methodology. Heterogeneity was low or absent for most outcomes, although there was moderate heterogeneity in the analysis of overall self-rated premenstrual symptoms. Based on the meta-analysis of response rate (the outcome with the most included studies), there was suspected publication bias. In total, 68% of the included studies were funded by pharmaceutical companies. This stresses the importance of interpreting the review findings with caution. AUTHORS' CONCLUSIONS: SSRIs probably reduce premenstrual symptoms in women with PMS and PMDD and are probably more effective when taken continuously compared to luteal phase administration. SSRI treatment probably increases the risk of adverse events, with the most common being nausea, asthenia and somnolence.

Luteal phase sertraline treatment of premenstrual dysphoric disorder (PMDD): Effects on markers of hypothalamic pituitary adrenal (HPA) axis activation and inflammation.

RATIONALE: Premenstrual dysphoric disorder (PMDD) is characterized by severe affective symptoms during the luteal phase of the menstrual cycle. There is some evidence of altered interactions between the hypothalamic pituitary gonadal (HPG) and hypothalamic pituitary adrenal (HPA) axes in PMDD. There is also evidence that similar affective disorders such as major depression and perinatal depression are associated with dysregulation in immune factors, but this has not been characterized in PMDD. AIMS: The goals of this exploratory study were to identify 1) whether HPA-HPG axis interactions and immune markers differ between PMDD patients and controls across the menstrual cycle; 2) how luteal phase sertraline treatment impacts stress and inflammatory markers. METHODS: Participants were females age 18-50 with regular menstrual cycles, not using psychotropic or hormonal medications, and were assigned to a control group or PMDD group based on prospective daily symptom ratings and clinical interview. Blood was drawn in the follicular and luteal phases, during laboratory sessions involving a mildly stressful task. In a second luteal phase, PMDD participants received open-label sertraline (50 mg/d) from ovulation to menses. Serum cortisol and ACTH were measured via ELISA and operationalized as area under the curve with respect to ground (AUCg), and peak level following laboratory task. Serum TNF-α, IL-6, CXCL-8, and IL-1ß were measured using multiplex kits. Serum allopregnanolone (ALLO) was measured by gas chromatography/mass spectroscopy. To characterize HPA-HPG axis interactions across the menstrual cycle in PMDD participants and controls, multilevel linear models predicted cortisol and ACTH from the interaction of cycle phase (controlling for sertraline treatment), ALLO, and group. To determine the effects of sertraline treatment on inflammatory markers and how groups might differ in cyclical change on each marker, multilevel linear models predicted inflammatory markers from cycle phase (controlling for sertraline treatment) and group. A final set of exploratory models tested whether inflammatory markers predict premenstrual symptom score severity. RESULTS: The sample included n=77 participants (41 controls, 36 PMDD); 28 participants with PMDD completed sertraline treatment. Group x phase x ALLO interactions showed that higher ALLO levels predicted lower cortisol peak in the treated luteal phase (interaction between phase and ALLO, p=0.042), and there was a higher cortisol peak in the treated luteal phase than the untreated luteal phase (p=0.038). CXCL-8 was significantly associated with premenstrual symptom severity after controlling for group and cycle phase (p=0.011). There were no main effects of group, phase, or ALLO on cortisol AUCg, ACTH AUCg, IL-6, CXCL-8, IL-1ß, nor TNF-α (p's>0.05). CONCLUSION: Serum markers of HPA axis and immune function did not vary by menstrual cycle phase nor PMDD status. However, sertraline treatment in the luteal phase was associated with higher ALLO levels predicting lower cortisol peak in response to mild laboratory stress, suggesting that sertraline treatment may normalize HPG-HPA axis interactions among individuals with PMDD. Greater premenstrual symptomatology was associated with higher levels of the inflammatory marker CXCL-8, but further research is needed into the potential role of inflammation in PMDD.

Rectal versus vaginal progesterone administration for luteal phase support in the hormone replacement therapy frozen embryo transfer (HRT-FET) cycle: protocol for a non-inferiority randomised controlled trial.

INTRODUCTION: This study compares rectal administration with vaginal administration of progesterone as luteal phase support in hormone replacement therapy frozen embryo transfer (HRT-FET) cycles. The reason for comparing the two routes of administration is that rectal administration has been suggested to be more patient friendly. METHODS AND ANALYSIS: This study is a randomised controlled trial comparing the ongoing pregnancy rate (OPR) at week 12 in HRT-FET cycles after rectal administered progesterone as the only administered progesterone compared with a vaginal luteal phase support regimen. All patients are enrolled from a Danish public fertility clinic and randomised to one of two groups, with 305 patients receiving embryo transfer assigned to each group. Endometrial preparation includes 6 mg oestradiol daily. The intervention group receives rectally administered progesterone (400 mg/12 hours) and the control group receives vaginally administered progesterone (400 mg/12 hours). If P4 is <35 nmol/L on blastocyst transfer day an additional rectal luteal phase rescue regimen is started (control group). Thawing and transferring of a single autologous vitrified blastocyst is scheduled on the sixth day of progesterone administration in both groups. The power calculation is based on a non-inferiority analysis with an expected OPR in both groups of 44% and the upper limit of a one-sided 95% CI will exclude a difference in favour of the control group of more than 10.0%. An interim analysis will be conducted once half of the study population has been enrolled. ETHICS AND DISSEMINATION: The trial was approved on 21 November 2023 by the Danish National Ethical Committee and the Danish Medicines Agency and is authorised by the Clinical Trials Information System (EUCT number 2023-504616-15-02). All patients will provide informed consent before being enrolled in the study. The results will be published in an international journal. TRIAL REGISTRATION NUMBER: EUCT number: 2023-504616-15-02.

Effect of occupational exposure to vat-textile dyes on follicular and luteal hormones in female dye workers in Abeokuta, Nigeria.

Background: Some synthetic dyes used mainly in textile industries have been associated with endocrine disruption, resulting in infertility, among other disorders. It is unknown if occupational exposure to Vat textile dyes among premenopausal dyers alters hormonal levels. Objectives: We aimed at determining the probable effects of occupational exposure to Vat dyes on reproductive hormones of female textile dyers in the follicular and luteal phases while relating this to age categories and duration of exposure. Methods: Thirty-three premenopausal Vat textile dyers at "Itoku", Abeokuta, Nigeria, among a population of about 80 female dyers were age and sex-matched with 55 non-exposed (control) female participants. Using semi-structured questionnaires, socio-demographic, occupational details and the LMP of participants were obtained. Serum samples were collected in follicular and luteal phases and assayed for female sex hormones using Enzyme Immunoassay. Mann-Whitney U and Z- statistic were used for comparison of the two groups. P-value < 0.05 was considered to be significant. Results: In the follicular phase, the result showed a lower mean FSH ranking (in age category ≤20 years) and higher (p<0.05) Estradiol ranking (in age category 31-40 years) in the exposed than the unexposed. Mean ranks of Progesterone and Estradiol in the luteal phase (age category 31-40 years) were higher (p<0.05) in the exposed, while Estradiol (age category ≥41years) ranked lower (p<0.05). Prolactin demonstrated a significant inverse relationship with the duration of exposure. Conclusion: Occupational exposure to Vat dye among female dyers in Abeokuta is associated with some sex hormone disruption which appears to be age and duration of exposure-related.

The natural menstrual cycle revisited - can natural cycle be trusted.

BACKGROUND: The serum progesterone (P4) level during the luteal phase (LP) plays a crucial role in the initiation and maintenance of pregnancy. However, it is unclear whether the natural cycle consistently provides the best endocrine profile and whether mid-luteal serum P4 levels are always sufficient to support implantation and early pregnancy. The question has become more relevant in relation to fertility treatment, as more frozen embryo transfer cycles are performed in the natural cycle. Moreover, can serum hormone levels and covariates measured during the follicular phase (FP), such as Follicle Stimulation Hormone (FSH), Luteinizing Hormone (LH), Estradiol (E2), Anti-Mullerian Hormone (AMH) and Antral Follicle Count (AFC), be used to predict P4 levels during the luteal phase (LP)? RESULTS: This observational prospective cohort study analysed 26 healthy women with a cycle length between 21-35 days and a body mass index (BMI) < 30 kg/m2. Blood sampling started on the fifth day of the menstrual cycle and continued every fifth day until the next cycle. The procedure was repeated for a total of three cycles. The study found that only ten women had a P4 level greater than 30 nmol/L on cycle day 20 or 25 in all three cycles. In total, only 45 cycles out of 77 cycles had serum P4 levels ≥ 30 nmol/L. The E2 level ≥ 345 pmol/L on cycle day 10 proved to be predictive of a P4 level of ≥ 30 nmol/L on either day 20 or day 25 with a sensitivity of 57% and a specificity of 89%. No other covariates, including the FSH level cycle day 5, LH levels during the follicular phase, age, weight, AFC and AMH cycle day 5 correlated with LP P4 levels. CONCLUSIONS: A significant correlation between FP E2 levels cycle day 5 (> 131pmol/L) and cycle day 10 (> 345pmol/L) and a LP P4 level ≥ 30 nmol/l was found; thus, the FP E2 level is a predictor of corpus luteum competence. Our findings highlight the existence of suboptimal P4 levels during the LP and a significant inter-individual and intra-cycle variation in P4 levels during the LP in regular menstruating women.

Luteal phase support with oral progesterone improves live birth rate in intrauterine insemination cycles using letrozole.

RESEARCH QUESTION: Does luteal phase support (LPS) with oral progesterone improve the live birth rate (LBR) in patients undergoing intrauterine insemination (IUI) cycles with letrozole? DESIGN: This retrospective cohort study included 1199 IUI cycles with letrozole between January 2017 and December 2021. A nearest neighbour random matching approach was employed to pair the LPS group and the control group in a 1:2 ratio. Eight variables were chosen for matching in the propensity score matching (PSM) model: age; body mass index; duration of infertility; cause(s) of infertility; antral follicle count; basal concentration of FSH; rank of IUI attempts; and leading follicle size. LBR was selected as the primary outcome. RESULTS: In total, 427 LPS cycles were matched with 772 non-LPS (control) cycles after PSM. The LBR was significantly higher in the LPS group compared with the control group (19.7% versus 14.5%; P = 0.0255). The clinical pregnancy rate (23.2% versus 17.6%; P = 0.0245) and ongoing pregnancy rate (20.6% versus 15.8%; P = 0.0437) were also significantly higher in the LPS group. The biochemical pregnancy rate, ectopic pregnancy rate and miscarriage rate were similar in the two groups (P > 0.05). The intergroup comparison revealed no significant variances in terms of gestational age, mode of delivery, ectopic pregnancy rate or abortion rate. Furthermore, there were no significant differences in birth weight or birth length between the two groups. CONCLUSIONS: Luteal support with oral progesterone significantly improved the LBR in IUI cycles with letrozole, but did not affect neonatal outcomes.

Undetected, natural conception pregnancies in luteal phase stimulations-case series and review of literature.

STUDY QUESTION: What is the risk of an undetected natural conception pregnancy during luteal phase ovarian stimulation, and how does it impact the pregnancy's course? SUMMARY ANSWER: The risk for an undetected, natural conception pregnancy in luteal phase ovarian stimulation is low and it appears that ovarian stimulation is unlikely to harm the pregnancy. WHAT IS KNOWN ALREADY: Random start ovarian stimulation appears to be similarly effective as early follicular stimulation start; and it allows ovarian stimulation to be started independent of the cycle day and throughout the cycle, in accordance with the patients' and clinics' schedule as long as there is no intention of a fresh embryo transfer in the same cycle. Starting ovarian stimulation in the luteal phase bears the possibility of an-at the timepoint of stimulation start-undetected, natural conception pregnancy that has already occurred. There is scarce data on the incidence of this event as well as on the possible implications of ovarian stimulation on the course of an existing pregnancy. STUDY DESIGN, SIZE, DURATION: This retrospective observational study, performed between June 2017 and January 2024, analyzed luteal phase stimulations, in which a natural conception pregnancy was detected during the ovarian stimulation treatment for IVF/ICSI. Luteal phase stimulation was defined as ovarian stimulation started after ovulation and before the next expected menstrual bleeding, with a serum progesterone (P4) level of >1.5 ng/ml on the day of stimulation start or 1 day before. PARTICIPANTS/MATERIALS, SETTING, METHODS: Women who underwent a luteal phase ovarian stimulation in a tertiary referral ART center. MAIN RESULTS AND THE ROLE OF CHANCE: A total of 488 luteal phase stimulation cycles were included in the analysis. Luteal phase stimulation was only started after a negative serum hCG measurement on the day or 1 day before commencement of ovarian stimulation. Ten patients (2.1%) had an undetected natural conception pregnancy at the time of luteal phase stimulation start. Eight of these patients underwent an ovarian stimulation in a GnRH-antagonist protocol and two in a progestin-primed stimulation protocol (PPOS). Recombinant FSH was used as stimulation medication for all patients, the patients with a PPOS protocol received additional recombinant LH. One pregnancy (0.2%) was detected after the oocyte retrieval, the other nine pregnancies were detected either due to persistent high serum progesterone levels or due to an increasing progesterone level after an initial decrease before oocyte retrieval. In the cycles with an undetected natural conception pregnancy, the median number of stimulation days was 8 days (range: 6-11 days) and median serum hCG at detection of pregnancy was 59 IU hCG (range: 14.91-183.1). From 10 patients with a pregnancy, three patients delivered a healthy baby, two patients had ongoing pregnancies at the time of summarizing the data, three patients had biochemical pregnancies (patient age: 30, 39, and 42 years), one patient had an ectopic pregnancy which required a salpingectomy, and one patient (age: 34 years) had an early pregnancy loss. LIMITATIONS, REASONS FOR CAUTION: The retrospective study design and the small sample size can limit the accuracy of the estimates. WIDER IMPLICATIONS OF THE FINDINGS: Overall, there is a small risk of undetected natural conception pregnancies when luteal phase stimulation is undertaken. It appears that there are no adverse effects through either direct effect on the embryo or indirectly through a detrimental effect on the corpus luteum function on the pregnancy in our cohort. STUDY FUNDING/COMPETING INTEREST(S): This study did not receive funding. The authors declare that there is no conflict of interest. TRIAL REGISTRATION NUMBER: N/A.

Pretreatment with luteal estradiol for programming antagonist cycles compared to no pretreatment in advanced age women stimulated with corifollitropin alfa: a non-inferiority randomized controlled trial.

STUDY QUESTION: Does luteal estradiol (E2) pretreatment give a similar number of retrieved oocytes compared to no-pretreatment in advanced-aged women stimulated with corifollitropin alfa in an antagonist protocol? SUMMARY ANSWER: Programming antagonist cycles with luteal E2 gave similar number of retrieved oocytes compared to no-pretreatment in women aged 38-42 years. WHAT IS KNOWN ALREADY: Programming antagonist cycles with luteal E2 pretreatment is a valuable tool to organize the IVF procedure better and is safe without any known impact on cycle outcome. However, variable effects were observed on the number of retrieved oocytes depending on the treated population. In advanced-age women, recruitable follicles tend to decrease in number and to be more heterogeneous in size but it remains unclear if estradiol pretreatment could change the oocyte yield through its negative feed-back effect on FSH intercycle rise. STUDY DESIGN, SIZE, DURATION: This non-blinded randomized controlled non-inferiority trial was conducted between 2016 and 2022 with centrally computerized randomization and concealed allocation. Participants were 324 women aged 38-42 years undergoing IVF treatment. The primary endpoint was the total number of retrieved oocytes. Statistical analysis was performed with one-sided alpha risk of 2.5% and 95% confidence interval (CI) with the non-inferiority of E2 pretreatment proved by a P value <0.025 and a lower delta margin of the CI within two oocytes compared to no pretreatment. Secondary endpoints were duration and total dosage of recombinant FSH, cancellation rate, percentage of oocyte pick-up (OPU) on working days, total number of metaphase II oocytes and obtained embryos, fresh transfer live birth rate, and cumulative live birth rate. PARTICIPANTS/MATERIALS, SETTING, METHODS: This multicentric study enrolled women with regular cycles, weight >50 kg and body mass index <32, IVF cycle 1-2. According to randomization, micronized estradiol 2 mg twice a day was started on days 20-24 and continued until Wednesday beyond the onset of menses followed by administration of corifollitropin alfa on Friday, i.e. stimulation (S)1 or from D1-3 of a natural cycle in unpretreated patients. GnRH antagonist was started at S6 and additional FSH at S8. MAIN RESULTS AND THE ROLE OF CHANCE: Basal characteristics were similar in patients randomized in E2 pretreated (n = 164) and non-pretreated (n = 160) groups (intended to treat (ITT) population). A total of 291 patients started treatment (per protocol (PP) population), 147 in E2 pretreated group with a mean number [SD] of pre-treatment days 9.8 [2.6] and 144 in the non-pretreated group. Despite advanced age, oocyte yields ranged from 0 to 29 in both groups with a median number of 6 retrieved oocytes in accordance with a mean anti-Müllerian hormone (AMH) level above 1.2 ng/ml. We demonstrated the non-inferiority of E2 pretreatment with a mean difference of -0.1 oocyte 95% CI [-1.5; 1.3] P = 0.004 in the PP population and a mean difference of -0.44 oocyte [-1.84; 0.97] P = 0.014 in the ITT population. Oocyte retrieval was more often on working days in E2 pretreated patients (91.9 versus 74.2%, P < 0.001). In patients reaching OPU, the duration of stimulation was statistically significantly longer (11.7 [1.7] versus 10.8 [1.8] days, P < 0.001) and the extra FSH dosage in addition to corifollitropin alfa was statistically significantly higher (1040 [548] versus 778 [504] IU, P < 0.001) in E2 pretreated than non-pretreated patients. We did not observe any significant differences in the number of retrieved oocytes (8.4 [6.1] versus 9.1 [6.0]), in the number of Metaphase 2 oocytes (7 [5.5] versus 7.3 [5.2]) nor in the number of obtained embryos (5 [4.6] versus 5.2 [4.2]) in E2 pretreated patients compared to non-pretreated patients. The live birth rate after fresh transfer (16.2% versus 18.5%, respectively), and the cumulative live birth rate per patient (17.7% versus 22.9%, respectively) were similar in both groups. Among the PP population, 31.6% of patients fulfilled the criteria for group 4 of Poseïdon classification (AMH <1.2 ng/ml and/or antral follicle count <5). In this sub-group of patients, we observed in contrast a statistically higher number of retrieved oocytes in E2 pretreated patients compared to non-pretreated (5.1 [3.8] versus 3.4 [2.7], respectively, the mean difference of +1.7 oocyte [0.2; 3.2] P = 0.022) but without significant difference in the cumulative live birth rate per patient (15.7% versus 7.3%, respectively). LIMITATIONS, REASONS FOR CAUTION: Our stimulated women older than 38 years obtained a wide range of collected oocytes suggesting very different stages of ovarian aging in both groups. E2 pretreatment is more likely to increase oocyte yield at the stage of ovarian aging characterized by asynchrony of a reduced follicular cohort. Another limitation is the sample size in sub-group analysis of patients with AMH <1.2 ng/ml. Finally, the absence of placebo for pretreatment could also introduce possible bias. WIDER IMPLICATIONS OF THE FINDINGS: Programming antagonist cycles with luteal E2 pretreatment seems a useful tool in advanced age women to better schedule oocyte retrievals on working days. However, the potential benefit of the number of collected oocytes remains to be demonstrated in a larger population displaying the characteristics of decreased ovarian reserve encountered in Poseïdon classification. STUDY FUNDING/COMPETING INTEREST(S): Research grant from (MSD) Organon, France. I.C., S.D., B.B., X.M., S.G., and C.J. have no conflict of interest with this study. I.C.D. declares fees as speaker from Merck KGaA, Gedeon Richter, MSD (Organon, France), Ferring, Theramex, and IBSA and participation on advisory board from Merck KGaA. I.C.D. also declares consulting fees, and travel and meeting support from Merck KGaA. N.M. declares grants paid to their institution from MSD (Organon, France); consulting fees from MSD (Organon, France), Ferring, and Merck KGaA; honoraria from Merck KGaA, General Electrics, Genevrier (IBSA Pharma), and Theramex; support for travel and meetings from Theramex, Merck KGaG, and Gedeon Richter; and equipment paid to their institution from Goodlife Pharma. N.C. declares grants from IBSA Pharma, Merck KGaA, Ferring, and Gedeon Richter; support for travel and meetings from IBSA Pharma, Merck KGaG, MSD (Organon, France), Gedeon Richter, and Theramex; and participation on advisory board from Merck KGaA. A.G.L. declares fees as speaker from Merck KGaA, Gedeon Richter, MSD (Organon, France), Ferring, Theramex, and IBSA. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov NCT02884245. TRIAL REGISTRATION DATE: 29 August 2016. DATE OF FIRST PATIENT'S ENROLMENT: 4 November 2016.

Menstrual cycle status does not impact exercise-based changes in cerebral blood flow or executive function benefits.

A single bout of exercise enhances executive function (EF) and may relate to an increase in cerebral blood flow (CBF). A limitation in the current literature is that biologically female participants are underrepresented given some evidence that changes in hormone levels across the menstrual cycle impact physiological and psychological variables. Here, biologically female participants completed separate single bouts of moderate intensity exercise (80% of estimated lactate threshold) during the follicular (FOL) and luteal (LUT) phases of their menstrual cycle. In addition, biologically male participants completed a same duration/intensity exercise session. Middle cerebral artery velocity (MCAv) was used to estimate CBF and pre- and postexercise EF was assessed via the antisaccade task. Results showed that resting MCAv was larger in the LUT than FOL phase; however, the exercise-mediated increase in MCAv was equivalent between menstrual cycle phases, and between female and male participants. Antisaccade reaction times reliably decreased from pre- to postexercise and frequentist and non-frequentist statistics demonstrated that the magnitude of the decrease was equivalent across FOL and LUT phases, and between female and male participants. Thus, results evince that menstrual cycle status should not serve as a basis limiting biologically female participants' inclusion in research examining exercise and EF.

Individualized luteal phase support in frozen-thawed embryo transfer after intramuscular progesterone administration might rectify live birth rate.

Background: The serum P concentrations are suggested to have an impact on pregnancy outcome. However there is no consensus about the optimal progesterone cut-off during the luteal phase. Few studies evaluated the effectiveness of a "rescue protocol" for low serum P concentrations and most of these studies used vaginal progesterone administration. There is paucity of data on the effectiveness of rescue protocol using intramuscular progesterone (IM-P) in frozen-thawed embryo transfer (FET). Methods: This study is a retrospective cohort study included 637 single or double blastocyst FETs with artificially prepared endometrium receiving 100 mg IM progesterone (P) after incremental estrogen treatment. Serum P concentrations were evaluated using blood samples obtained 117-119 hours after the first IM-P administration and 21 ± 2 hours after the last IM-P administration. Patients with serum P concentrations <20.6 ng/ml on the ET day were administrated 400 mg vaginal progesterone for rescue. Results: Demographic and cycle characteristics were similar between patients receiving rescue vaginal P (embryo transfer (ET)-day P concentration < 20.6 ng/ml) and patients who did not need rescue vaginal P (ET-day P concentration ≥ 20.6 ng/ml). Clinical pregnancy, miscarriage, and live birth rates were similar between two groups: 52.9%(45/85) vs 59.6%(326/552), p=0.287; 11.1%(5/45) vs 14.1%(46/326), p=0.583; and 47.1%(40/85) vs 50.7%(280/552), p=0.526, respectively. Logistic regression analysis revealed that the female age (p = 0.008, OR=0.942, 95% CI = 0.902-0.984) and embryo quality (ref: good quality for moderate: p=0.02, OR=0.469, 95% CI =0.269-0.760; for poor: p=0.013, OR= 0.269, 95% CI = 0.092-0.757) were independent variables for live birth. Following rescue protocol implementation, ET-day P concentration was not a significant predictor of live birth. Conclusions: Rescue vaginal P administration for low ET day serum P concentrations following IM-P yields comparable live birth rates.

Comparison of luteal support protocols in fresh IVF/ICSI cycles: a network meta-analysis.

Despite the proven superiority of various luteal phase support protocols (LPS) over placebo in view of improved pregnancy rates in fresh cycles of IVF (in vitro fertilization) and ICSI (intracytoplasmic sperm injection) cycles, there is ongoing controversy over specific LPS protocol selection, dosage, and duration. The aim of the present study was to identify the optimal LPS under six core aspects of ART success, clinical pregnancy, live birth as primary outcomes and biochemical pregnancy, miscarriage, multiple pregnancy, ovarian hyperstimulation syndrome (OHSS) events as secondary outcomes. Twelve databases, namely Embase (OVID), MEDLINE (R) (OVID), GlobalHealth (Archive), GlobalHealth, Health and Psychosocial Instruments, Maternity & Infant Care Database (MIDIRS), APA PsycTests, ClinicalTrials.gov, HMIC Health Management Information Consortium, CENTRAL, Web of Science, Scopus and two prospective registers, MedRxiv, Research Square were searched from inception to Aug.1st, 2023, (PROSPERO Registration: CRD42022358986). Only Randomised Controlled Trials (RCTs) were included. Bayesian network meta-analysis (NMA) model was employed for outcome analysis, presenting fixed effects, odds ratios (ORs) with 95% credibility intervals (CrIs). Vaginal Progesterone (VP) was considered the reference LPS given its' clinical relevance. Seventy-six RCTs, comparing 22 interventions, and including 26,536 participants were included in the present NMA. Overall CiNeMa risk of bias was deemed moderate, and network inconsistency per outcome was deemed low (Multiple pregnancy χ2: 0.11, OHSS χ2: 0.26), moderate (Clinical Pregnancy: χ2: 7.02, Live birth χ2: 10.95, Biochemical pregnancy: χ2: 6.60, Miscarriage: χ2: 11.305). Combinatorial regimens, with subcutaneous GnRH-a (SCGnRH-a) on a vaginal progesterone base and oral oestrogen (OE) appeared to overall improve clinical pregnancy events; VP + OE + SCGnRH-a [OR 1.57 (95% CrI 1.11 to 2.22)], VP + SCGnRH-a [OR 1.28 (95% CrI 1.05 to 1.55)] as well as live pregnancy events, VP + OE + SCGnRH-a [OR 8.81 (95% CrI 2.35 to 39.1)], VP + SCGnRH-a [OR 1.76 (95% CrI 1.45 to 2.15)]. Equally, the progesterone free LPS, intramuscular human chorionic gonadotrophin, [OR 9.67 (95% CrI 2.34, 73.2)] was also found to increase live birth events, however was also associated with an increased probability of ovarian hyperstimulation, [OR 1.64 (95% CrI 0.75, 3.71)]. The combination of intramuscular and vaginal progesterone was associated with higher multiple pregnancy events, [OR 7.09 (95% CrI 2.49, 31.)]. Of all LPS protocols, VP + SC GnRH-a was found to significantly reduce miscarriage events, OR 0.54 (95% CrI 0.37 to 0.80). Subgroup analysis according to ovarian stimulation (OS) protocol revealed that the optimal LPS across both long and short OS, taking into account increase in live birth and reduction in miscarriage as well as OHSS events, was VP + SCGnRH-a, with an OR 2.89 [95% CrI 1.08, 2.96] and OR 2.84 [95% CrI 1.35, 6.26] respectively. Overall, NMA data suggest that combinatorial treatments, with the addition of SCGnRH-a on a VP base result in improved clinical pregnancy and live birth events in both GnRH-agonist and antagonist ovarian stimulation protocols.