Successful reproductive management of domestic mammals depends primarily upon timely identification of oestrous cycle stages. There is a need to develop an alternative non-invasive, welfare-friendly, accurate and reliable method to identify reproductive cycle stages. This is of particular interest for horse breeders, because horses are high-value farm animals that require careful management and individual monitoring. Saliva sampling is non-invasive, painless and welfare-friendly. Thus, we performed a metabolomic analysis of equine saliva during different reproductive stages to identify changes in the salivary metabolome during anoestrus, the oestrous cycle and early gestation. We compared the saliva and plasma metabolomes to investigate the relationship between the two fluids according to the physiological stage. We collected saliva and plasma samples from six mares during seasonal anoestrus, during the follicular phase 3 days, 2 days and 1 day before ovulation and the day when ovulation was detected, during the luteal phase 6 days after ovulation, and during early gestation 18 days after ovulation and insemination. Metabolome analysis was performed by proton-nuclear magnetic resonance spectroscopy. We identified 58 and 51 metabolites in saliva and plasma, respectively. The levels of four metabolites or groups of metabolites in saliva and five metabolites or groups of metabolites in plasma showed significant modifications during the 4 days until ovulation, ie 3 days prior to and on the day of ovulation. The levels of 11 metabolites or groups of metabolites in saliva and 17 metabolites or groups of metabolites in plasma were significantly different between the seasonal anoestrus and the ovarian cyclicity period. The physiological mechanisms involved in the onset of ovarian cyclicity and in ovulation induced modifications of the metabolome both in plasma and saliva. The metabolites whose salivary levels changed during the reproductive cycle could be potential salivary biomarkers to detect the reproductive stage in a welfare friendly production system. In particular, we propose creatine and alanine as candidate salivary biomarkers of ovulation and of the onset of ovarian cyclicity, respectively. However, extensive validation of their reliability is required. Our study contributes to extend to domestic mammals the use of saliva as a non-invasive alternative diagnostic fluid for reproduction in a welfare-friendly production system.

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.
OBJECTIVE: To evaluate the benefits and harms of SSRIs in treating women diagnosed with PMS and PMDD.
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.
METHODS: We considered studies in which women with a prospective diagnosis of PMS, PMDD or LLPDD were randomised to receive SSRIs or placebo.
METHODS: 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.
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.
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.

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.
CONCLUSIONS: 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.

OBJECTIVE: The queen is recognised as an induced ovulator. Ovulation without male contact is generally regarded as spontaneous. The aim of this study was to provide an estimate of the incidence of spontaneous ovulation in a population of intact queens presented to a veterinary care facility for both reproductive and non-reproductive reasons. The secondary objective was to determine the roles of age, breed, body weight, presence of tom cats or other cycling queens, and physical contact with humans on triggering spontaneous ovulation, along with its implications.
METHODS: Serum samples from post-pubertal intact queens presented between January 2020 and June 2023 to the Veterinary Teaching Hospital of the University of Padova, Italy, were retrieved and assayed for progesterone (P4) levels. Serum P4 above 2.0 ng/ml without a history of male contact was considered as proof of spontaneous ovulation.
RESULTS: In total, 31 serum samples from 29 intact post-pubertal queens were obtained. Of the 31 samples, 14 had a P4 concentration above 2.0 ng/ml and 9/29 (31.0%) queens ovulated spontaneously. The mean age and weight of the nine spontaneously ovulating queens were 4.3 ± 5.7 years and 3.7 ± 0.8 kg, respectively. One queen ovulated spontaneously at her first heat at 6 months of age, which makes it the earliest spontaneous ovulation reported.
CONCLUSIONS: As both our findings and previous publications indicate that the incidence of spontaneous ovulation in queens is consistently ⩾30%, cats should not be considered strictly induced ovulators, but as a species in which ovulation can be either spontaneous or induced. Since the risk of progesterone-dependent conditions (cystic endometrial hyperplasia - pyometra complex, feline mammary hypertrophy) is increased in these queens, veterinarians should be aware and advise breeders and clients accordingly.
Female cats ovulate upon vaginal stimulation exerted by the spikes of the male’s penis while mating, which makes them induced ovulators. When ovulation occurs without male contact, it is considered spontaneous. There are several factors that are thought to facilitate this non-induced ovulation, but no consensus on their relevance. The aim of this study was to provide an estimate of the rate of spontaneous ovulation in a population of intact female cats of various breeds presented to a veterinary care facility, as well as the influence of factors such as age, breed, body weight, presence of male cats or other cycling females, and physical contact with humans on triggering spontaneous ovulation. In addition, possible implications arising from progesterone exposure were assessed.Progesterone was retrospectively assayed in the serum of adult cycling female cats presented to the Veterinary Teaching Hospital of the University of Padova, Italy, between January 2020 and June 2023. Values above 2.0 ng/ml without a history of male contact were considered proof of spontaneous ovulation. Out of 29 cats, nine (31%) ovulated spontaneously, with one female having done so at puberty (6 months of age), which makes it the first spontaneous ovulation ever reported in a pubertal queen.As spontaneous ovulation has been found to occur at a rate of more than 30% both in our and in previous publications on this topic, we propose that cats should be considered both an induced and a spontaneously ovulating species. Since animals that ovulate spontaneously, and therefore experience additional luteal phases, are at a higher risk of developing progesterone-dependent conditions, veterinarians should be aware and advise breeders and clients accordingly.

The effects of female sex hormones on optimal performance have been increasingly recognized as an important consideration in exercise and sport science research. This narrative review explores the findings of studies evaluating the effects of menstrual cycle phase in eumenorrheic women and the use of hormonal contraception (oral contraceptives and hormonal intrauterine devices) on metabolism, muscular strength, and recovery in active females. Ovarian hormones are known to influence metabolism because estrogen is a master regulator of bioenergetics. Importantly, the menstrual cycle may impact protein synthesis, impacting skeletal muscle quality and strength. Studies investigating muscular strength in eumenorrheic women report equivocal findings between the follicular phase and luteal phase with no differences compared to oral contraceptive users. Studies examining recovery measures (using biomarkers, blood lactate, and blood flow) do not report clear or consistent effects of the impact of the menstrual cycle or hormonal contraception use on recovery. Overall, the current literature may be limited by the evaluation of only one menstrual cycle and the use of group means for statistical significance. Hence, to optimize training and performance in females, regardless of hormonal contraception use, there is a need for future research to quantify the intra-individual impact of the menstrual cycle phases and hormonal contraceptive use in active females.

Testosterone production in women is thought to systematically shift across the menstrual cycle, peaking during the mid-cycle ovulatory window, and potentially influencing women\'s behavior. Testosterone is a molecular intermediary to the production of estradiol, which is necessary for ovulation to occur, but the amount of testosterone escape and exposure to the peripheral tissues is not fully understood. Salivary testosterone is a common biomarker in behavioral neuroendocrinological studies and is thought to reflect the bioactive portions in serum. In N = 339 women with confirmed ovulation via luteinizing hormone tests, salivary testosterone, assayed with LC-MS/MS, was sampled four times across the mid-cycle ovulatory window the luteal phase. Within-subject analysis revealed a significant but small pattern of a mid-cycle peak and a luteal decrease at the aggregate level. However, at the individual level, there was substantial variability in the direction and magnitude of the testosterone-cycle pattern. We discuss the relevant underlying physiology, background research, issues with assay methodolody, and considerations for researchers studying testosterone levels in women.

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.

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.

BACKGROUND: A low progesterone level on the embryo transfer (ET) day significantly reduces the pregnancy rate. Therefore, the present study aims to investigate the effect of adding daily 50 mg intramuscular progesterone to a total of 800 mg progesterone suppository on the in vitro fertilization (IVF) success rate in women with low progesterone levels.
METHODS: This parallel open-label clinical trial was performed on 218 IVF candidate infertile women who had <9.2 ng/ml progesterone levels on the ET day. These women were randomised to the intervention or control group using the randomisation allocation rule. In the intervention group, 50 mg progesterone was prescribed intramuscularly once daily in addition to 400 mg of progesterone suppository every 12 hours from the day of ET. The control group received only 400 mg of progesterone suppositories every 12 hours. In the case of pregnancy, the drugs above were continued until 12 weeks after the ET.
RESULTS: Clinical pregnancy occurred in 54 (50.0%) women in the intervention group and in 39 (36.8%) women in the control group, which was significantly different (P=0.035). Ongoing pregnancy occurred in 47 (43.5%) women in the intervention group, and 33 (31.1%) women in the control group, which was significantly different (P=0.042). There were no significant differences in terms of abortion and multiple pregnancy rates between the two groups.
CONCLUSIONS: Intramuscular injection of 50 mg progesterone significantly increases the clinical and ongoing pregnancy rates (registration number: IRCT20150105020558N6).

UNASSIGNED: 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).
UNASSIGNED: 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.
UNASSIGNED: 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.
UNASSIGNED: Rescue vaginal P administration for low ET day serum P concentrations following IM-P yields comparable live birth rates.