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Fertility awareness-based methods (FABMs), also known as natural family planning (NFP), enable couples to identify the days of the menstrual cycle when intercourse may result in pregnancy ("fertile days"), and to avoid intercourse on fertile days if they wish to avoid pregnancy. Thus, these methods are fully dependent on user behavior for effectiveness to avoid pregnancy. For couples and clinicians considering the use of an FABM, one important metric to consider is the highest expected effectiveness (lowest possible pregnancy rate) during the correct use of the method to avoid pregnancy. To assess this, most studies of FABMs have reported a method-related pregnancy rate (a cumulative proportion), which is calculated based on all cycles (or months) in the study. In contrast, the correct use to avoid pregnancy rate (also a cumulative proportion) has the denominator of cycles with the correct use of the FABM to avoid pregnancy. The relationship between these measures has not been evaluated quantitatively. We conducted a series of simulations demonstrating that the method-related pregnancy rate is artificially decreased in direct proportion to the proportion of cycles with intermediate use (any use other than correct use to avoid or targeted use to conceive), which also increases the total pregnancy rate. Thus, as the total pregnancy rate rises (related to intermediate use), the method-related pregnancy rate falls artificially while the correct use pregnancy rate remains constant. For practical application, we propose the core elements needed to assess correct use cycles in FABM studies. Summary: Fertility awareness-based methods (FABMs) can be used by couples to avoid pregnancy, by avoiding intercourse on fertile days. Users want to know what the highest effectiveness (lowest pregnancy rate) would be if they use an FABM correctly and consistently to avoid pregnancy. In this simulation study, we compare two different measures: (1) the method-related pregnancy rate; and (2) the correct use pregnancy rate. We show that the method-related pregnancy rate is biased too low if some users in the study are not using the method consistently to avoid pregnancy, while the correct use pregnancy rate obtains an accurate estimate. Short Summary: In FABM studies, the method-related pregnancy rate is biased too low, but the correct use pregnancy rate is unbiased.

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Free-ranging nilgai antelope (Boselaphus tragocamelus) are an understudied species, both on their native ranges of India, Pakistan, and Nepal and on their introduced ranges in southern Texas. Basic data related to population sizes, survival, reproduction, and recruitment are needed throughout their range to inform management and conservation decisions. We collected nilgai fetuses from 3 ranches in southern Texas, including East Foundation's El Sauz and Santa Rosa ranches, and the Norias Division of the King Ranch® from 2018-2021. We calculated the percentage of individuals that were pregnant in each of the sample years and overall. We determined monthly average, maximum, and minimum fetus length. Of 488 nilgai cows, we found 386 to be pregnant (79%) and 214 to be pregnant with twins (56%). We found nilgai cows as young as 1-year old to have fetuses and therefore to have reached sexual maturity. Sex ratios of fetuses during any sampling year did not differ. We found ample evidence supporting our hypothesis that nilgai are fecund on their introduced range of southern Texas. To prevent nilgai overpopulation and associated problems, harvest management strategies should be implemented, specifically on nilgai cows.

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Perfluoroalkyl and polyfluoroalkyl substances (PFASs), widely utilized in various industries, may pose potential reproductive well-being risks. However, the research on the impact of PFAS exposures on pregnancy and live birth rates remains scarce. To address this gap, we conducted a cross-sectional study using the data from the United States National Health and Nutrition Examination Survey (NHANES) collected between 2013 and 2018. We focused on six PFAS compounds measured in the serum of women aged 20 to 50 years, employing the Poisson regression, Quantile G-composition (Qgcomp), and Weighted Quantile Sum (WQS) regression models. Adjusting for age, racial/ethnic origin, educational level, marital status, family income, body mass index (BMI), menarche age, birth control pill use, and other female hormone consumption, the Poisson regression identified significant negative associations between the individual PFAS exposures and pregnancy and live birth numbers (p < 0.05 for all 24 null hypotheses for which the slope of the trend line is zero). The Qgcomp analysis indicated that a one-quartile increase in the mixed PFAS exposures was associated with reductions of 0.09 (95% CI: -0.15, -0.03) in the pregnancy numbers and 0.12 (95% CI: -0.19, -0.05) in the live birth numbers. Similarly, the WQS analysis revealed that a unit increase in the WQS index corresponded to decreases of 0.14 (95% CI: -0.20, -0.07) in the pregnancy numbers and 0.14 (95% CI: -0.21, -0.06) in the live birth numbers. Among the six specific PFAS compounds we studied, perfluorononanoic acid (PFNA) had the most negative association with the pregnancy and live birth numbers. In conclusion, our findings suggest that PFAS exposures are associated with lower pregnancy and live birth numbers among women of reproductive age.

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BACKGROUND: Microsurgical vasoepididymostomy is an effective surgical method for treating epididymal obstructive azoospermia but the surgical outcomes can be affected in some non-vasectomized epididymal obstructive azoospermia patients with concurrent vas-deferens obstruction. This study aimed to explore the clinical characteristics and surgical outcomes in non-vasectomized epididymal obstructive azoospermia patients with versus without concurrent vas-deferens obstruction. STUDY DESIGN: Retrospective study. OBJECTIVE: To explore the clinical characteristics and surgical outcomes in non-vasectomized epididymal obstructive azoospermia patients with versus without concurrent vas-deferens obstruction, aiming to identify predictive factors for concurrent vas-deferens obstruction and evaluate the efficacy of microsurgical vasoepididymostomy in patients with epididymal obstructive azoospermia and concurrent short-segment vas-deferens obstruction. MATERIALS AND METHODS: A retrospective analysis of 225 epididymal obstructive azoospermia cases was conducted at the First Affiliated Hospital of Fujian Medical University from November 2016 to March 2023. All patients underwent a comprehensive preoperative evaluation. During surgery, the vas deferens were assessed to determine the presence and extent of obstruction. Depending on the obstruction length, either a standard microsurgical vasoepididymostomy was performed, or the obstructed segment was resected followed by microsurgical vasoepididymostomy. If the remaining length post-resection was insufficient for anastomosis, the procedure was discontinued. Data on patient clinical characteristics, operative findings, and outcomes were collected and analyzed. Logistic regression was used to identify predictive factors for concurrent vas-deferens obstruction, and comparative analysis assessed patency and pregnancy rates between patients with and without concurrent vas-deferens obstruction. RESULTS: Of the 225 patients in the study, 77 (34.22%) presented with epididymal obstructive azoospermia and concurrent vas-deferens obstruction. Logistic regression analysis revealed that "the history of epididymitis" was a significant predictive factor for epididymal obstructive azoospermia patients with concurrent vas-deferens obstruction (odds ratio = 9.06, p < 0.001). The average length of vas deferens obstruction amenable to microsurgical vasoepididymostomy post-resection was 1.31 ± 0.54 cm (range from 0.50 to 2.50 cm). In contrast, cases unsuitable for microsurgical vasoepididymostomy presented an average obstruction length of 15.26 ± 5.79 cm (p < 0.001). The patency rates were 82.17% in epididymal obstructive azoospermia patients without concurrent vas-deferens obstruction and 74.14% in those with concurrent vas-deferens obstruction. The pregnancy rates followed a similar trend, at 34.11% and 34.48%, respectively. These differences were not statistically significant (p > 0.05 for both). However, epididymal obstructive azoospermia patients with vas-deferens obstruction exhibited a decreased likelihood of bilateral microsurgical vasoepididymostomy (p < 0.001). DISCUSSION AND CONCLUSION: Our study identifies a noticeable occurrence of concurrent vas-deferens obstruction in non-vasectomized epididymal obstructive azoospermia patients, with approximately one-third of the cases (34.22%) exhibiting vas-deferens obstruction during surgical interventions. Notably, a small fraction (6.67%) of these individuals chose not to proceed with any microsurgical vasoepididymostomy, even on one side, due to the extensive length of the obstruction. Through logistic analysis, we have demonstrated that "the history of epididymitis" is a critical predictive factor for the presence of vas-deferens obstruction, underscoring its significance in preoperative evaluations. Furthermore, our research confirms that microsurgical vasoepididymostomy is still an effective treatment for epididymal obstructive azoospermia patients with concurrent short-segment vas-deferens obstruction, achieving significant patency and favorable pregnancy rates compared to those patients without vas-deferens obstruction. These insights are pivotal for enhancing surgical strategies and improving fertility outcomes in this patient cohort.

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OBJECTIVE: To investigate the potential impact of vitamin D (VD) serum levels on couples going through in vitro fertilization treatment in terms of embryo quality and pregnancy rates. DESIGN: A retrospective cohort study. SETTING: A private human reproduction center. PATIENT(S): A total of 267 couples underwent intracytoplasmic sperm injections between January 2017 and March 2019. INTERVENTION(S): The couples were categorized into four groups on the basis of 25-hydroxy VD (25OHD) levels measured at the beginning of the stimulation protocol: group 1 with 25OHD levels ≥30 ng/mL for both women and men; group 2 with 25OHD levels <30 ng/mL for both; group 3 women with 25OHD levels <30 ng/mL and men with 25OHD levels ≥30 ng/mL; and group 4 with women with 25OHD level ≥30 ng/mL and men with 25OHD level <30 ng/mL. MAIN OUTCOME MEASURE(S): We consider the quantity and quality of embryos during the cleavage as well as blastocyst stages as primary outcomes. Correspondingly, the clinical pregnancy rate (CPR) was regarded as a secondary outcome. RESULT(S): Our findings revealed no significant correlations between the studied VD groups and the evaluated outcomes. This includes the quantity and quality of embryos during the cleavage and blastocyst stages, as well as the CPR. Primary analysis revealed a small but statistically significant difference in the duration of controlled ovarian stimulation between group 1 and group 2 (95% confidence interval, 0.07-3.04) and between group 1 and group 3 (95% confidence interval, 0.05-3.23). CONCLUSION(S): The present study found no correlation between the studied VD levels and the quantity as well as quality of cleavage or blastocyst stage embryos, nor did it show any impact on CPRs. Further well-designed, prospective studies are warranted to determine whether and how vitamin D affects reproductive outcomes.

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The aim of this study was to evaluate the effects of medroxyprogesterone acetate (MPA) treatment in comparison to those of gonadotropin releasing hormone (GnRH) antagonists for the prevention of premature luteinizing hormone surges during controlled ovarian hyperstimulation (OS) and the impact of these effects on developing embryos and pregnancy outcomes. Data from 757 cycles of GnRH antagonist treatment and 756 cycles of MPA treatment were evaluated at the Akdeniz University Faculty of Medicine Assisted Reproductive Treatment Center between October 2018 and April 2022. Patient records were obtained from the electronic database of the centre and analysed. In our centre, GnRH antagonist protocols were used between 2018 and 2020, and MPA protocols were used between 2020 and 2022. We chose our study population by year. Our study is a comparative retrospective study. All methods in this study were performed in accordance with the relevant guidelines and regulations. Patients using MPA were significantly older (33.9 ± 5.6 vs. 32.6 ± 5.6, p < 0.001) and had a lower number of antral follicles (AFC) (10.7 ± 8.6 vs. 11.9 ± 10.8, p = 0.007) than those using GnRH antagonists. Both MPA (2.9%) and GnRH antagonists (2.2%) had similar effectiveness in preventing premature ovulation (p = 0.415). There was no significant difference between the two groups in terms of the number of total developed embryos (1.3 ± 1.3 vs. 1.2 ± 1.2, p = 0.765). There was no significant difference in the clinical pregnancy rates with the first ET (%35.4 vs. %30.1, p = 0.074), per total number of transfers (35.3% vs. 30.1%, p = 0.077). MPA was found to be effective at preventing premature ovulation during OS treatment, and the incidence of developing embryo and pregnancy outcomes in patients using MPA were similar to those in patients using GnRH antagonists. Therefore, the use of MPA instead of GnRH antagonists during OS may be a viable alternative for patients not scheduled for fresh ET.

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OBJECTIVES: The objective of the study was to evaluate the prevalence and impact of impaired thyroid-stimulating hormone (TSH) levels on the reproductive outcomes of in vitro fertilization patients diagnosed with endometriosis and compared to controls without endometriosis. DESIGN: This is a retrospective cohort study on prospectively collected data. SETTING: The study was conducted at tertiary care university hospital. PARTICIPANTS: Participants were infertile women with histopathological diagnosis of endometriosis. METHODS: For 12 months (January 2018 to January 2019), women were deemed suitable and subsequently divided according to serum TSH levels above or below 2.5 mIU/L and compared to patients without endometriosis. Needed sample size was at least 41 patients for each cohort of women. Co-primary outcomes were the live birth rate (LBR), clinical pregnancy rate (CPR), and pregnancy loss rate (PLR). RESULTS: Overall, 226 women (45 with endometriosis and 181 controls without endometriosis) were included. Diagnoses of Hashimoto thyroiditis were significantly more frequent in women with rather than without endometriosis (14/45 [31.1%] vs. 27/181 [14.9%]; p = 0.012). Similarly, in women with endometriosis, Hashimoto diagnosis rates were higher with TSH ≥2.5 mIU/L compared to TSH <2.5 mIU/L (9/15 [60%] vs.5/30 [16.6%]; p = 0.001) so were the Hashimoto diagnosis rates in control group (women without endometriosis) with TSH ≥2.5 mIU/L compared to TSH <2.5 mIU/L (17/48 [35.4%] vs. 10/133 [7.5%], respectively; p = 0.001). Effect size analysis confirmed an increased risk of Hashimoto thyroiditis in women with endometriosis and TSH ≥2.5 mIU/L compared to women with endometriosis and TSH <2.5 mIU/L (risk ratio [RR] 3.60 [95% CI 1.46-8.86]) and in women with endometriosis and TSH ≥2.5 mIU/L compared to non-endometriotic euthyroid patients (RR 7.98 [95% CI 3.86-16.48]). Dysmenorrhea risk was higher in endometriotic euthyroid women compared to euthyroid patients with no endometriosis (RR 1.87 [95% CI 1.21-2.87]). The risk was still increased in euthyroid women with endometriosis relative to dysthyroid women with no endometriosis (RR 1.97 [95% CI 1.11-3.50]). There were no significant differences between the four groups for CPR, LBR, PLR and retrieved oocytes, immature oocytes, degenerated and unfertilized oocytes, cultured blastocysts, embryos and transferred embryos. LIMITATIONS: Limitations of the study were retrospective design, limited sample size, and use of different ovarian stimulation protocol. CONCLUSIONS: Thyroid autoimmunity seems more common in women with endometriosis and TSH over 2.5 mIU/L. However, there was no significant impact on in vitro fertilization and reproductive outcomes related to the coexistence of endometriosis, Hashimoto disease, and higher TSH levels. Due to limitations of the study, additional evidence is required to validate the abovementioned findings.

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BACKGROUND: Polycystic ovary syndrome (PCOS) is a prevalent endocrine disorder associated with infertility and pregnancy complications. The pathogenesis of PCOS and its impact on reproductive function may be influenced by the source of androgens, including testosterone, free androgen, dehydroepiandrosterone sulfate (DHEAS). However, the differential effects of these androgen on pregnancy and neonatal outcomes and the cut-off value of East Asian population with PCOS remain unclear. METHODS: A retrospective cohort study was conducted at the Reproductive Medicine Center of the First Affiliated Hospital of Sun Yat-sen University from January 2015 to November 2022, involving 636 cycles of in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI). Subgroup analyses were performed using cut-off values of 6.4 for free androgen index (FAI), 9.5 µmol/L for DHEAS. Pregnancy and neonatal outcomes were compared between groups. Restricted cubic spline (RCS) was used to identify significant cut-off values affecting pregnancy. RESULTS: Higher FAI levels (> 6.4) were associated with decrease in clinical pregnancy rate (PR) (50.61% vs. 41.66%, p = 0.024), live birth rate (LBR) (42.42% vs. 32.35%, p = 0.011). When DHEAS levels exceeded 9.5 µmol/L, there was a significant decrease in clinical PR (51.27% vs. 42.73%, P = 0.039), LBR (42.73% vs. 32.73%, P = 0.012). Negative correlations were also observed between DHEAS levels and cumulative pregnancy rate (70.57% vs 56.62% p = 0.002) and cumulative live birth rate (CLBR) (59.35% vs 43.37%, p = 0.0007). Both FAI and DHEAS elevated is associated with the lowest clinical pregnancy rate (37.84%). Conversely, when solely FAI is elevated, the pregnancy rate increases to 52.38%, while an elevation in DHEAS alone is associated with a pregnancy rate of, both of which are lower than when neither FAI nor DHEAS are elevated (60.68%). The live birth rates exhibit a similar trend (30.00% vs 40.00% vs 41.83% vs 44.48%). RCS revealed a significant decrease in CPR and CLBR when DHEA levels exceeded 7.69 umol/L, while the cut-off value of FAI was 6.36 for CPR and CLBR. CONCLUSION: In conclusion, PCOS patients with biochemical hyperandrogenism show unsatisfactory clinical PR and CLBR when undergoing assisted reproductive technology (ART). This may be attributed to the influence of both adrenal-derived DHEAS and ovarian-derived FAI on the unfavorable pregnancy outcomes.

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Purpose: This study aims to evaluate the developmental potential of 0PN, 1PN, and 2PN zygotes in IVF cycles and compare their clinical outcomes. Methods: We conducted a retrospective cohort study involving IVF patients. Blastocyst formation rates were assessed with 0PN, 1PN, and 2PN zygotes. Subsequently, we collected clinical outcome data following the transfer of these zygotes. Results: The overall blastulation rate was similar between 0PN (29.6%) and 2PN (32.1%) zygotes, but 1PN zygotes exhibited a significantly lower blastulation rate (17.0%) compared to both 0PN and 2PN zygotes. Similarly, the overall rate of good-quality blastulation was comparable between 0PN (15.3%) and 2PN (17.5%) zygotes, while 1PN zygotes showed a significantly lower rate (7.0%) compared to both 0PN and 2PN. Clinical pregnancy, ectopic pregnancy, implantation, and live birth rates were similar among single blastocyst frozen embryo transfers (FET) of 0PN, 1PN, and 2PN. Additionally, no significant differences were observed between single- and double-blastocyst FET of 0PN and 2PN. Conclusions: Our findings suggest that 0PN and 2PN zygotes have comparable developmental potential, while 1PN embryos exhibit lower developmental potential. Blastocyst FET outcomes appear similar among 0PN, 1PN, and 2PN zygotes.

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OBJECTIVE: To propose a new classification system (Urman-Vitale Classification System) for intrauterine adhesions (IUAs) and to evaluate anatomical and fertility outcomes after hysteroscopic adhesiolysis accordingly. METHODS: A retrospective analysis of consecutive patients treated over 11 years by a single operator in a tertiary care hospital. Women with sonographic suspicion of IUAs were scheduled for hysterosalpingography (HSG) and hysteroscopy for confirmation and treatment. IUAs were divided into five classes according to symptoms, ultrasound, HSG findings, and postsurgical hysteroscopic appearance. Hysteroscopic adhesiolysis was performed using a bipolar cutting electrode in an office setting. Evaluated outcomes were restoration of the uterine cavity, clinical pregnancy, pregnancy loss, and live birth rates. RESULTS: A total of 227 patients (479 procedures) were included. Mean number of hysteroscopies increased in frequency with class of adhesions from Class 1 to Class 5 (1.0 ± 0.2 vs 2.3 ± 0.5; P = 0.001). Full restoration of the cavity was achieved in 100% of patients with Class 1 compared with 18.5% for Class 5 (43/43 vs 5/27; P = 0.001). Clinical pregnancy (Class 1 vs Class 4: P = 0.034; 1 vs 5: P = 0.006; 2 vs 5: P = 0.024) and live birth (Class 1 vs Class 4: P = 0.001; 1 vs 5: P = 0.006; 2 vs 4: P = 0.007; 2 vs 5: P = 0.0208) rates decreased with increasing severity of IUAs. Pregnancy loss rate was related to IUA severity (Class 1 vs Class 4: P = 0.012; 1 vs 5: P = 0.003: 2 vs 4: P = 0.014; 2 vs 5: P = 0.021). CONCLUSION: A classification based on symptoms, imaging findings, and postsurgical macroscopic appearance of the uterine cavity could be useful in predicting prognosis and fertility in women with IUAs.

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OBJECTIVE: This study aimed to investigate whether hysteroscopy plus endometrial fundal incision (EFI) with endoscopic scissors can improve reproductive outcomes in oocyte recipients who have failed in their first egg donation cycle. METHODS: This was a prospective study (2014-2022) conducted in Assisting Nature Centre Reproduction and Genetics, Thessaloniki Greece, IVF Unit. The study population consisted of oocyte recipients with implantation failure in their first embryo transfer (ET) with donor eggs. All the recipients underwent routine evaluation during their early follicular phase, 1-3 months before the start of a new cycle with donor oocytes and were eligible to undergo EFI. RESULTS: During the study period, 218 egg recipients underwent egg donation; 126 out of 218 oocyte recipients (57.8%) did not achieve a live birth at the 1st ET. 109 of them had surplus embryos cryopreserved and underwent a second ET; 50 women consented for EFI. Both groups were similar in terms of age, years of infertility, duration of estrogen replacement protocol and number of transferred blastocysts (p>0.05). In the EFI group, 60% had normal intrauterine cavity, while 40% had minor anomalies. The pregnancy test was positive in 46% (n=23/50) in the EFI group compared with 27.1% (n=16/59) in the control group (p=0.04). Moreover, live birth rates were higher in the EFI group compared to the control group (38.0% vs. 20.3%; p=0.04). CONCLUSIONS: The findings of our study indicate that in oocyte recipients after implantation failure, diagnostic hysteroscopy plus EFI prior to subsequent ETmay increase pregnancy and live birth rates.

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INTRODUCTION: Usefulness of hysteroscopy before assisted reproductive technique (ART) was considered debatable. However, over the last decade, several new trials have been added to available literature. We aimed to assess the impact of diagnostic and operative hysteroscopy on reproductive outcomes of infertile women with and without intrauterine abnormalities. MATERIALS AND METHODS: MEDLINE, Scopus, SciELO, Embase, Cochrane Library at CENTRAL, PROSPERO, CINAHL, grey literature, conference proceedings, and international controlled trials registries were searched without temporal, geographical, or language restrictions. Randomized controlled trials (RCTs) of infertile women comparing hysteroscopy versus no hysteroscopy prior to the first ART or after at least one failed attempt were included. RCTs of infertile women with intrauterine pathology comparing diagnostic versus operative hysteroscopy were included in separate analysis. Random-effect meta-analysis was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Grading of Recommendations, Assessment, Development and Evaluation and Cochrane criteria were used for quality of evidence and risk of bias assessment. Primary outcome was live birth rate (LBR). Secondary outcomes were clinical pregnancy (CPR) and pregnancy loss rate. RESULTS: Fifteen studies (5,038 women) were included. Compared to no hysteroscopy before first or after failed ART attempts, moderate-quality evidence showed that hysteroscopy increased the LBR (relative risk [RR] 1.24, 95% confidence interval [CI] 1.09-1.43, I2 = 21%), confirmed by subgroup analysis for women with failure after one or more ART cycles (RR 1.43, 95% CI: 1.19-1.72, I2 = 0%) but not before the first ART. Moderate-quality evidence showed that it increased the CPR (RR 1.36, 95% CI: 1.18-1.57; I2 = 51%), confirmed in subgroup analysis for both implantation failure (RR 1.40, 95% CI: 1.12-1.74, I2 = 52%) and before first ART (RR 1.32, 95% CI: 1.11-1.57, I2 = 42%). Low-quality data suggest that operative hysteroscopy increases CPR when used to treat intrauterine pathologies (RR 2.13, 95% CI: 1.56-2.92, I2 = 0%). CONCLUSIONS: Although moderate-quality evidence supports performing hysteroscopy before ART in women with history of implantation failure, hysteroscopic evaluation of uterine cavity should be considered a first-line technique in all infertile women undergoing ART. Additional high-quality RCTs are still needed, particularly to assess yield during couple's initial evaluation even before ART is considered.

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Migration patterns are fundamentally linked to the spatio-temporal distributions of prey. How migrating animals can respond to changes in their prey's distribution and abundance remains largely unclear. During the last decade, humpback whales (Megaptera novaeangliae) used specific winter foraging sites in fjords of northern Norway, outside of their main summer foraging season, to feed on herring that started overwintering in the area. We used photographic matching to show that whales sighted during summer in the Barents Sea foraged in northern Norway from late October to February, staying up to three months and showing high inter-annual return rates (up to 82%). The number of identified whales in northern Norway totalled 866 individuals by 2019. Genetic sexing and hormone profiling in both areas demonstrate a female bias in northern Norway and suggest higher proportions of pregnancy in northern Norway. This may indicate that the fjord-based winter feeding is important for pregnant females before migration. Our results suggest that humpback whales can respond to foraging opportunities along their migration pathways, in some cases by continuing their feeding season well into winter. This provides an important reminder to implement dynamic ecosystem management that can account for changes in the spatio-temporal distribution of migrating marine mammals.

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Background and objectives Polycystic ovary syndrome (PCOS) is a prominent cause of anovulation. Thus, this study aimed to compare the pregnancy rates of women with PCOS treated with letrozole (LE) or clomiphene citrate (CC) at King Abdulaziz University Hospital. Patients and methods A retrospective record review was conducted from April 2021 to August 2022 to review 1370 records of women with PCOS from January 2015 to December 2021. Sixty-one patients were included in this analysis. Chi-square tests and independent sample t-tests were used to analyze various associations. Statistical significance was set at P < 0.05. Results Letrozole was associated with a higher pregnancy rate (41.7%) than CC (32.0%). However, this relationship was not statistically significant (P = .619). Furthermore, patients treated with letrozole required fewer cycles to achieve pregnancy (two cycles compared to three cycles). The different age groups and body mass indexes did not affect the pregnancy rate in either group. Conclusion No significant difference was found between CC and LE in ovulation induction and outcome among PCOS patients. Studies with larger sample sizes and multiple centers should be conducted in Saudi Arabia to obtain more conclusive results, which will eventually lead to changes in guidelines for anovulation treatment in women with PCOS.

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Las mujeres posponen su maternidad por el deseo de superación personal y profesional. Se conoce que la cantidad y calidad de los óvulos por ciclo dependen de la edad de la paciente. Las tasas de éxito en tratamientos de reproducción asistida disminuyen con la edad, especialmente después de los 40 años. Se observan tasas más altas de nacidos vivos en mujeres más jóvenes y las tasas disminuyen significativamente en mujeres mayores debido a la disminución de la fertilidad y el aumento de abortos espontáneos. Por ello, la edad es crucial al evaluar la posibilidad de un embarazo exitoso mediante tratamientos de reproducción asistida (TRA). Las indicaciones para realizar fertilización in vitro (FIV) con óvulos propios en mujeres mayores de 40 años incluyen iniciar lo más pronto procedimientos de alta complejidad, buena evaluación de la reserva ovárica con análisis de la hormona antimülleriana y conteo de folículos antrales para realizar asesoramiento genético, proponer FIV-inyección intracitoplasmática de espermatozoides (ICSI) antes de los 44 años, generar expectativas realistas y realizar consentimiento informado, con estadisticas propias. En la REDLARA, de todos los procedimientos de FIV-ICSI, el 34% de las pacientes tienen más de 40 años; se prefiere transferir blastocistos con prueba genética preimplantacional de aneuploidías (PGT-A) para seleccionar embriones euploides. Las tasas de éxito son bajas, inclusive cuando son tasas de embarazo por transferencia de un embrión en el grupo de mujeres ≥ 40 años (18,2% sin PGT, 42,7% con PGT en el IMRCRP). Se recomienda acumular óvulos o embriones realizando múltiples estimulaciones ováricas. Se debe optar por transferir un solo embrión para evitar complicaciones obstétricas con embarazos múltiples en pacientes ≥ 40 años, por el alto riesgo debido a la edad.

Women postpone motherhood because of their desire for personal and professional improvement. It is known that the quantity and quality of oocytes per cycle depends on the patient's age. Success rates in assisted reproduction treatments decrease with age, especially after 40 years of age. Higher live birth rates are observed in younger women, and rates decrease significantly in older women due to decreased fertility and increased miscarriages. Therefore, age is crucial when assessing the possibility of a successful pregnancy through assisted reproductive treatments (ART). The indications to perform in vitro fertilization (IVF) with own ovules in women older than 40 years include starting as soon as possible highly complex procedures, good evaluation of ovarian reserve with antimüllerian hormone analysis (AMH) and antral follicle count (AFC) for genetic counseling, proposing IVF-intracytoplasmatic sperm injection (ICSI) before the age of 44 years, generating realistic expectations and informed consent, with own statistics. At REDLARA, of all IVF-ICSI procedures, 34% of patients are over 40 years old; preference is given to transfer blastocysts with preimplantation genetic testing for aneuploidy (PGT-A) to select euploid embryos. Success rates are low, even when they are pregnancy rates per embryo transfer in the group of women ≥ 40 years (18.2% without PGT, 42.7% with PGT in IMRCRP). It is recommended to bank ovules or embryos by performing multiple ovarian stimulations. A single embryo transfer should be chosen to avoid obstetric complications with multiple pregnancies in patients ≤ 40 years, because of the high risk due to age.

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Ganirelix is a gonadotropin-releasing hormone (GnRH) antagonist with high antagonistic activity that blocks the GnRH receptor by competitive binding. A daily dose of 0.25 mg of ganirelix was sel5ected after a phase II study because it was the minimal, effective daily dose to prevent premature luteinizing hormone surges and this dose yielded the highest ongoing pregnancy rate per started cycle. After subcutaneous administration, ganirelix is rapidly absorbed, reaching peak levels within 1-2 hours (tmax), and has a high absolute bioavailability (>90%). Prospective, comparative studies have demonstrated the advantages of GnRH antagonists over long GnRH agonist treatment in assisted reproduction, including the immediate reversibility of drug effects, a requirement for less follicle-stimulating hormone, a shortened duration of stimulation, a reduced incidence of ovarian hyperstimulation syndrome, and reduced patient burden. Combined analyses concluded that in the general in vitro fertilization population, there is a trend for a slightly lower ongoing pregnancy rate and a lower risk of ovarian hyperstimulation syndrome that is largely eliminated when considering triggering with GnRH agonist instead of human chorionic gonadotropin. Regardless of all the research, it is still not fully elucidated why the long GnRH agonist protocol has a trend for higher pregnancy rates after fresh transfer of the same number of good-quality embryos.

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BACKGROUND: Uterine blood flow determines endometrial thickness. This study examined how vaginal sildenafil citrate and estradiol valerate altered endometrial thickness, blood flow, and fertility in infertile women. METHODS: This study observed 148 infertile women whose infertility was unexplained. Group 1 comprised 48 patients who received oral estradiol valerate (Cyclo-Progynova 2 mg/12 h white tablets) from day 6 till ovulation was initiated with clomiphene citrate. A number of 50 participants in group 2 received oral sildenafil (Respatio 20 mg/12 h film-coated tablets) for 5 days starting the day after their previous menstrual period and finishing on the day they ovulated with clomiphene citrate. Group 3 was the control group, with 50 patients receiving clomiphene citrate (Technovula 50 mg/12 h tablets) ovulation induction from the 2nd to 7th day of cycle. All patients had transvaginal ultrasounds to determine ovulation, follicle count, and fertility. Miscarriage, ectopic pregnancy, and multiple pregnancies were monitored for three months. RESULTS: The three groups' mean ETs differed statistically at p = 0.0004. A statistically significant difference was found between the three groups in terms of the number of follicles, with 69% of patients in group 1 having one and 31% having two or more, 76% of patients in group 2 having one and 24% having two or more, and 90% of patients in the control group having one and 10% having two or more (p = 0.038). The clinical pregnancy rates of the three groups were 58%, 46%, and 27%, respectively (p = 0.005). The distribution of all side effects was not statistically different between the three groups. CONCLUSION: It is possible to claim that adding oral estrogen to clomiphene citrate therapy as an adjuvant therapy can improve endometrial thickness and, as a result, increase the pregnancy rates in unexplained infertility compared to sildenafil, especially in cases where the infertility has lasted less than two years. Most people who take sildenafil end up with a mild headache.

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Horses and donkeys differ phenotypically and karyotypically, although they can interbreed freely. Eight Standardbred mares and nine Amiata donkey jennies were included in the study. Semen was collected from two horses and two donkey stallions of proven fertility. A first pregnancy diagnosis was performed on day 10 after ovulation and repeated every day until embryo detection or until day 16. Irrespectively of the sire species, pregnancy rates in horse females (20/30, 66.7%) were significantly higher than in donkey females (19/70, 27.1%) (p < 0.05), while horse and donkey males did not affect pregnancy rates. Comparing overall intraspecific and interspecific AI, pregnancy rates were 25/37 (67.6%) and 14/63 (22.2%), respectively (p = 0.0001). The lowest pregnancy rate was obtained when inseminating jennies with horse stallion semen (8/49, 16.3%). No statistical differences were found when comparing embryo diameters, day at first pregnancy diagnosis, or in vitro embryo morphological quality among groups. In this study, much poorer results were obtained with jennies than with mares. Interspecific AI resulted in lower pregnancy rates than intraspecific Al, and AI to produce hinny hybrids resulted in the lowest pregnancy rate. Further studies are required to better understand the mechanism involved in such different outcomes in relation to intra- and interspecific breeding in domestic equids.

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The krill surplus hypothesis of unlimited prey resources available for Antarctic predators due to commercial whaling in the 20th century has remained largely untested since the 1970s. Rapid warming of the Western Antarctic Peninsula (WAP) over the past 50 years has resulted in decreased seasonal ice cover and a reduction of krill. The latter is being exacerbated by a commercial krill fishery in the region. Despite this, humpback whale populations have increased but may be at a threshold for growth based on these human-induced changes. Understanding how climate-mediated variation in prey availability influences humpback whale population dynamics is critical for focused management and conservation actions. Using an 8-year dataset (2013-2020), we show that inter-annual humpback whale pregnancy rates, as determined from skin-blubber biopsy samples (n = 616), are positively correlated with krill availability and fluctuations in ice cover in the previous year. Pregnancy rates showed significant inter-annual variability, between 29% and 86%. Our results indicate that krill availability is in fact limiting and affecting reproductive rates, in contrast to the krill surplus hypothesis. This suggests that this population of humpback whales may be at a threshold for population growth due to prey limitations. As a result, continued warming and increased fishing along the WAP, which continue to reduce krill stocks, will likely impact this humpback whale population and other krill predators in the region. Humpback whales are sentinel species of ecosystem health, and changes in pregnancy rates can provide quantifiable signals of the impact of environmental change at the population level. Our findings must be considered paramount in developing new and more restrictive conservation and management plans for the Antarctic marine ecosystem and minimizing the negative impacts of human activities in the region.

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