The ovarian stimulation regimen does not affect aneuploidy or blastocyst rate.

RESEARCH QUESTION: Could the total dose (<3000 IU or ≥3000 IU) and type of exogenous gonadotrophin (i.e. recombinant FSH and/or human menopausal gonadotrophin [HMG]) influence aneuploidy and blastulation rates and produce different reproductive outcomes? DESIGN: This retrospective, observational, multicentre cohort study included a total of 8466 patients undergoing IVF using autologous oocytes and preimplantation genetic testing for aneuploidies. Participants were divided according to the dosage of total gonadotrophins and stratified by maternal age. RESULTS: The aneuploidy rates, pregnancy outcomes and cumulative live birth rates (CLBR) were similar among women who received total gonadotrophin dosages of <3000 or ≥3000 IU. No statistical differences were reported in the blastulation rate with lower or higher gonadotrophin dosages. Women receiving a higher amount of HMG during ovarian stimulation had a lower aneuploidy rate (P = 0.02); when stratified according to age, younger women with a higher HMG dosage had lower aneuploidy rates (P< 0.001), while no statistical differences were observed in older women with higher or lower HMG dosages. No significant differences were observed in IVF outcomes or CLBR. CONCLUSIONS: High doses of gonadotrophins were not associated with rate of aneuploidy. However, an increased fraction of HMG in younger women was associated with a lower aneuploidy rate. The study demonstrated that the total gonadotrophin dosage did not influence aneuploidy, reproductive outcomes or CLBR. The increased gonadotrophin and HMG dosages used for ovarian stimulation did not precede aneuploidy, and the use of HMG should be evaluated on a case-by-case basis, according to the individual's characteristics and infertility type.

The effect of male factors on embryo morphokinetics: a retrospective analysis of 2726 blastocysts.

PURPOSE: Male infertility may influence fertilization rates, embryo morphology, and implantation rates in in vitro fertilization (IVF) cycles. Oocyte competence plays a major role in embryo development, but there is a limited understanding of the connection between sperm quality, embryo development, and morphokinetic parameters using donor oocytes. The study evaluated if sperm quality may influence the morphokinetic parameters in IVF cycles. METHODS: A retrospective multicentric observational cohort study included 747 ICSI cycles using donor oocytes with fresh or frozen sperm. Embryos were cultured in time-lapse incubators until the blastocyst stage. The population was divided into three groups according to sperm concentration, as control group (> 16 mill/mL), severe oligospermia (0-5 mill/mL), and moderate oligospermia group (5-16 mill/mL). RESULTS: Morphokinetic analysis showed no difference in the time from the 2-cell to 6-cell stage of embryo development. A significant difference was observed on day 3 of embryo development, specifically at the 7-cell stage (t7), severe oligospermia 53.37 ± 9.81, moderate oligospermia 56.95 ± 9.78, and control 55.1 ± 8.85 h post-insemination (hpi) (p = 0.024), and 8-cell stage (t8), severe oligospermia 55.41 ± 10.83, moderate oligospermia 61.86 ± 12.38 hpi (p < 0.001), and control 58.61 ± 11.33. Accordingly, the synchrony of the four cleavages going from 4 to 8 cells (s3) was found statistically different among the groups in the severe oligospermia 8.05 ± 9.99, moderate oligospermia 11.66 ± 11.04 hpi, and control 8.55 ± 8.58 (p = 0.009). Morphokinetic time ranges were obtained for t6, t7, t8, and s3 in order to identify the good-quality blastocysts. CONCLUSIONS: Poor sperm quality is associated with alterations in morphokinetic parameters on day 3 in IVF cycles with donor oocytes, underlining the important role of spermatozoa during embryo development.

Preimplantation genetic testing for aneuploidy is not related to adverse obstetric and neonatal outcomes in singleton pregnancies.

STUDY QUESTION: What is the potential impact of preimplantation genetic testing for aneuploidy (PGT-A) on obstetric and neonatal outcomes? SUMMARY ANSWER: PGT-A is not associated with increased rates of adverse maternal and neonatal outcomes in singleton pregnancies following IVF/ICSI cycles. WHAT IS KNOWN ALREADY: PGT-A pregnancies may be associated with increased risks of lower birthweight, preterm delivery, and hypertensive disorders compared with natural pregnancies. In a recent meta-analysis, the overall obstetric and neonatal outcomes of PGT-A pregnancies were favorable compared with those of IVF/ICSI pregnancies, although PGT-A pregnancies were associated with a higher risk of hypertensive disorders. STUDY DESIGN, SIZE, DURATION: A multicenter retrospective cohort study was performed in University-affiliated infertility centers. Single live births following IVF/ICSI between October 2016 and January 2021 were included in the study. PARTICIPANTS/MATERIALS, SETTING, METHODS: A total of 7146 live births after single embryo transfers with (n = 3296) or without (n = 3850) PGT-A were included. The primary outcome was pre-eclampsia and secondary outcomes included gestational diabetes, low birthweight and very low birthweight, cesarean section delivery, emergency cesarean section, as well as preterm birth, birthweight, congenital abnormalities, neonatal sex, Apgar score at 5 min, and neonatal intensive care unit admission. In a subgroup analysis, were included only blastocysts screened with next-generation sequencing (NGS). MAIN RESULTS AND THE ROLE OF CHANCE: Univariate analysis showed that pre-eclampsia, cesarean section incidence, and low Apgar score were higher in women undergoing PGT-A. However, after performing multivariate logistic and linear regression models accounting for many possible confounders, pregnancies that had been conceived after embryo biopsy showed no increase in adverse obstetric and neonatal outcomes. The subgroup analysis including patients with blastocysts screened by NGS showed a decreased risk of preterm birth in the group undergoing PGT-A. LIMITATIONS, REASONS FOR CAUTION: Caution should be used when interpreting the data because of its limitations, mainly related to its retrospective design. Although this is a large multicenter study, data acquisition included self-reporting questionnaires, and the deliveries occurred in different institutions with distinct protocols. WIDER IMPLICATIONS OF THE FINDINGS: The current study does not show any major adverse clinical outcomes after PGT-A. Efforts should be made to promote good quality research on embryo biopsy in terms of neonatal and obstetric outcomes, as well as its long-term consequences. STUDY FUNDING/COMPETING INTEREST(S): No specific funding was obtained for this study. The authors declare no conflicts of interest. TRIAL REGISTRATION NUMBER: N/A.

Pituitary suppression with GnRH agonists before ART may be insufficient to treat women with severe adenomyosis.

RESEARCH QUESTION: Does aromatase inhibitor improve IVF outcomes by reducing local oestrogen production in patients with adenomyosis undergoing long-term gonadotrophin-releasing hormone agonist (GnRHa) treatment? DESIGN: Four patients with severe adenomyosis who failed to improve after long-term treatment (≥3 months) with depot GnRHa received treatment with an aromatase inhibitor for 21 days. Blood oestradiol concentrations were monitored after GnRHa treatment both before and after treatment with an aromatase inhibitor. Women received a transfer of IVF autologous or donor oocytes. Pregnancy and ongoing pregnancy rates were the primary outcomes. Blood oestradiol concentration after treatment with an aromatase inhibitor was a secondary outcome. RESULTS: Patients with severe adenomyosis presented with hyperestrogenism due to local production from the lesions even after long-term treatment with GnRHa. Treatment with an aromatase inhibitor reduced hyperestrogenism and improved clinical outcomes in adenomyosis patients who have experienced previous embryo transfer failures. CONCLUSION: Women with severe adenomyosis would benefit from letrozole or a combination of GnRHa plus letrozole before receipt of treatment with assisted reproductive technology. For women with severe adenomyosis, GnRHa treatment alone may be insufficient to suppress oestrogen production by adenomyotic lesions. Thus, it should be mandatory to test for oestradiol concentrations in patients with severe adenomyosis who have received long-term GnRHa treatment. Also, GnRHa may not always be the sole strategy for medical management of adenomyotic lesions. Letrozole is safe and can improve IVF outcomes for patients with adenomyosis.

Ovarian rescue in women with premature ovarian insufficiency: facts and fiction.

The ovary has a comparatively short functional lifespan compared with other organs, and genetic and pathological injuries can further shorten its functional life. Thus, preserving ovarian function should be considered in the context of women with threats to ovarian reserve, such as ageing, premature ovarian insufficiency (POI) and diminished ovarian reserve (DOR). Indeed, one-third of women with POI retain resting follicles that can be reactivated to produce competent oocytes, as proved by the in-vitro activation of dormant follicles. This paper discusses mechanisms and clinical data relating to new therapeutic strategies using ovarian fragmentation, stem cells or platelet-rich plasma to regain ovarian function in women of older age (>38 years) or with POI or DOR. Follicle reactivation techniques show promising experimental outcomes and have been successful in some cases, when POI is established or DOR diagnosed; however, there is scarce clinical evidence to warrant their widespread clinical use. Beyond these contexts, also discussed is how new insights into the biological mechanisms governing follicular dynamics and oocyte competence may play a role in reversing ovarian damage, as no technique modifies oocyte quality. Additional studies should focus on increasing follicle number and quality. Finally, there is a small but important subgroup of women lacking residual follicles and requiring oocyte generation from stem cells.

The international transportation of frozen embryos does not affect IVF outcomes.

PURPOSE: The regulated transportation of cryopreserved human embryos resulting from assisted reproduction treatments offers opportunities for patients undergoing embryo transfer in other regions/countries. However, the principal concern for fertility clinics is maintaining unaltered embryo quality to ensure satisfactory clinical outcomes. The aim of the study was to evaluate the efficacy of the transportation process comparing the survival rate and competence of transported embryos to embryos produced and transferred on-site, in frozen embryo transfer cycles. METHODS: This retrospective study assessed the outcomes of 621 blastocysts thawed at IVI Roma (Italy) between March 2021 and March 2022. Autologous or donated oocytes fertilized in vitro, cultured to the blastocyst stage, and cryopreserved in IVI Roma clinic (Group A, n = 450), were compared to embryos generated in IVI Spain clinics and transported to IVI Roma (Group B, n = 171). RESULTS: Groups A and B respectively showed no significant difference in embryo survival rates after thawing (N = 440/450, 97.8% vs. N = 168/171, 98.2%, p = 0.71), pregnancy rates (N = 221/440, 50.23% vs. N = 77/168, 45.83%, p = 0.33), clinical pregnancy rates (N = 200/440, 45.45% vs. N = 62/168, 36.90%, p = 0.06), and miscarriage rates (N = 42/221, 19,00% vs. 21/77, 28.57%, p = 0.13), even after stratification for the source of the oocyte. Logistic binomial regression considering donor oocytes, preimplantation genetic testing, and patients' age, did not show any significant results on embryo survival and IVF outcomes. CONCLUSION: The regulated transport of cryopreserved blastocysts did not affect embryo survival rate or IVF outcomes. Our data support the safety of embryo cryopreservation and medical transportation services, allowing clinics and patients to transport embryos with no significant risk to embryo competence.

Use of dopamine agonists to target angiogenesis in women with endometriosis.

Endometriosis requires medical management during a woman's reproductive years. Most treatments aim to create a hypoestrogenic milieu, but for patients wishing to conceive, drugs that allow normal ovarian function are needed. Targeting angiogenesis, a hallmark of the disease, using dopamine agonists (DAs) is a promising strategy for endometriosis treatment. Herein, we review experimental and clinical data that investigate this concept. In experimental models of endometriosis, DAs (bromocriptine, cabergoline, quinagolide) downregulate proangiogenic and upregulate antiangiogenic pathways in inflammatory, endothelial and endometrial cells, blocking cellular proliferation and reducing lesion size. Impaired secretion of vascular endothelial growth factor (VEGF) and inactivation of its receptor type-2 are key events. VEGF inhibition also reduces nerve fiber density in lesions. In humans, quinagolide shows similar effects on lesions, and DAs reduce pain and endometrioma size. Moreover, a 20-fold downregulation of Serpin-1, the gene that encodes for plasminogen activator inhibitor 1 (PAI-1), has been observed after DAs treatment. Pentoxifylline, a PAI-1, increases pregnancy rates in women with endometriosis. Thus, the data support the use of DAs in the medical management of endometriosis to reduce lesion size and pain while maintaining ovulation. A combined approach of DAs and pentoxifylline is perhaps a smart way of targeting the disease from a completely different angle than current medical treatments.

COVID-19 and assisted reproductive technology services: repercussions for patients and proposal for individualized clinical management.

The prolonged lockdown of health services providing high-complexity fertility treatments -as currently recommended by many reproductive medicine entities- is detrimental for society as a whole, and infertility patients in particular. Globally, approximately 0.3% of all infants born every year are conceived using assisted reproductive technology (ART) treatments. By contrast, the total number of COVID-19 deaths reported so far represents approximately 1.0% of the total deaths expected to occur worldwide over the first three months of the current year. It seems, therefore, that the number of infants expected to be conceived and born -but who will not be so due to the lockdown of infertility services- might be as significant as the total number of deaths attributed to the COVID-19 pandemic. We herein propose remedies that include a prognostic-stratification of more vulnerable infertility cases in order to plan a progressive restart of worldwide fertility treatments. At a time when preventing complications and limiting burdens for national health systems represent relevant issues, our viewpoint might help competent authorities and health care providers to identify patients who should be prioritized for the continuation of fertility care in a safe environment.

A picture of the covid-19 impact on IVIRMA fertility treatment clinics in Spain and Italy.

The emergence of the novel coronavirus infection that arose in Wuhan, China in December 2019 has resulted in an epidemic that has quickly expanded to become one of the most significant public health threats in recent times. Unfortunately, the disease has spread globally. On March 11th (2020) World Health Organization (WHO) declared Covid-19 a pandemic and has called governments to take urgent and aggressive action to change the course of the outbreak. Within the context of Assisted Reproduction, both reproductive medicine professionals and patients are also fighting against this unprecedented viral pandemic. In view of events, most of us had to make serious decisions, some of them with a lack of scientific evidence due to the circumstances and with the only objective of ensuring the safe care of our patients, reduce non-essential contacts and prevent possible maternal and fetal complications in future pregnancies. Pregnant women should not be considered at high risk for developing severe infection. Up to date, there are no reported deaths in pregnant women with Covid-19, while in the cases that have presented pneumonia because of Covid-19, the symptoms have been moderate and with a good prognosis in recovery.

Dysmorphic Uterus: More Questions than Answers.

A T-shaped uterus is a rare uterine malformation that is classically associated with diethylstilbesterol (DES) exposure. Surprisingly, the prevalence of T- and Y-shaped uterus has increased in recent years despite the absence of a diagnostic consensus and a correlation with the reproductive outcomes has been observed. A systematic electronic database search for all English-language studies published on reproductive outcomes associated with dysmorphic uteri over the past 10 years using PubMed, Google Scholar, and Scopus was performed. This uterine malformation is associated with impaired reproductive outcomes, including primary infertility, miscarriage, ectopic pregnancy, and preterm birth. Hysteroscopic metroplasty is a simple surgical procedure that could potentially improve outcomes in subfertile women, but the data are not robust. Studies reported significant improvements in implantation and pregnancy rates after corrective metroplasty in women undergoing in vitro fertilization. However, multicenter, prospective, randomized, and controlled trials are needed to validate these findings and to help define clear diagnostic criteria, surgical indications, and appropriate follow-up of reproductive outcomes after the procedure.

Adenomyosis: An Update Concerning Diagnosis, Treatment, and Fertility.

This review article aims to summarize current tools used in the diagnosis of adenomyosis with relative pharmacological and surgical treatment and to clarify the relative association between adenomyosis and infertility, considering the importance of an accurate diagnosis of this heterogeneous disease. Among different reported concepts, direction invagination of gland cells from the basalis endometrium deep into the myometrium is the most widely accepted opinion on the development of adenomyosis. Adenomyosis has been increasingly identified in young women with pain, AUB, infertility, or no symptoms by using imaging techniques such as transvaginal ultrasound and magnetic resonance. Furthermore, adenomyosis often coexists with other gynecological conditions, such as endometriosis and uterine fibroids, increasing the heterogeneity of available data. However, there is no agreement on the definition and classification of adenomyotic lesions from both the histopathology and the imaging points of view, and diagnosis remains difficult and unclear. A standard, universally accepted classification system needs to be implemented to improve our understanding and inform precise diagnosis of the type of adenomyosis. This could be the key to designing RCT studies and evaluating the impact of adenomyosis on quality of life in terms of menstrual symptoms, fertility, and pregnancy outcome, given the high risk of miscarriage and obstetric complications.

Impact of adenomyosis on in vitro fertilization outcomes in women undergoing donor oocyte transfers: a prospective observational study.

OBJECTIVE: To prospectively examine the association between adenomyosis type, location, and severity with reproductive outcomes in patients undergoing single embryo transfer (SET) with embryos derived from donor oocytes. DESIGN: A prospective observational cohort study. SETTING: University-affiliated in vitro fertilization center. PATIENTS: Patients with infertility with (n = 114) and without (n = 114) adenomyosis who received their first donor oocyte transfer between January 2019 and January 2023 were included in this study. INTERVENTIONS: Adenomyosis was confirmed with the presence of at least one direct feature visualized by 2- or 3-dimensional transvaginal ultrasound and classified according to type (diffuse or focal), localization (inner or outer myometrium and/or junctional zone [JZ]), and uterine extension (mild, moderate, or severe). After an artificial or natural endometrial preparation cycle, patients underwent SET in the blastocyst stage. MAIN OUTCOME MEASURES: The primary outcome was the implantation rate. The secondary outcomes were the clinical pregnancy, live birth, and miscarriage rates after SET. RESULTS: The presence of adenomyosis did not significantly affect the implantation, clinical pregnancy, or live birth rates. However, women with adenomyosis had a significantly higher miscarriage rate than those without adenomyosis (35.4% vs. 18.1%, respectively). The multivariate analysis assessed possible risk factors for each clinical outcome considered in the study and showed that adenomyosis affected the risk of miscarriage. Specifically, transvaginal sonography detection of adenomyosis in the JZ was associated with over threefold higher relative risk of miscarriage (relative risk [RR], 3.28; 95% confidence interval [CI], 1.38-7.78). Conversely, adenomyosis features detected exclusively in the outer myometrium were associated with a higher ongoing pregnancy rate (RR, 0.30; 95% CI, 0.13-0.72). Diffuse adenomyosis in the JZ and severe adenomyosis increased the relative risk of miscarriage two-fold (RR, 2.29; 95% CI, 1.22-4.30 and RR, 2.20; 95% CI, 1.19-4.04, respectively). CONCLUSIONS: This study demonstrated that although adenomyosis did not significantly reduce the odds of implantation, the direct signs of adenomyosis in the JZ and disease severity are significant risk factors for miscarriage in patients receiving donor oocyte transfers. This study highlights the importance of thorough ultrasound examination and detailed adenomyosis classification in the assessment and management of patients with infertility.

Oocyte vitrification for fertility preservation is an evolving practice requiring a new mindset: societal, technical, clinical, and basic science-driven evolutions.

Infertility is a condition with profound social implications. Indeed, it is not surprising that evolutions in both medicine and society affect the way in vitro fertilization is practiced. The keywords in modern medicine are the four principles, which implicitly involve a constant update of our knowledge and our technologies to fulfill the "prediction" and "personalization" tasks, and a continuous reshaping of our mindset in view of all relevant societal changes to fulfill the "prevention" and "participation" tasks. A worldwide aging population whose life priorities are changing requires that we invest in fertility education, spreading actionable information to allow women and men to make meaningful reproductive choices. Fertility preservation for both medical and nonmedical reasons is still very much overlooked in many countries worldwide, demanding a comprehensive update of our approach, starting from academia and in vitro fertilization laboratories, passing through medical offices, and reaching out to social media. Reproduction medicine should evolve from being a clinical practice to treat a condition to being a holistic approach to guarantee patients' reproductive health and well-being. Oocyte vitrification for fertility preservation is the perfect use case for this transition. This tool is acquiring a new identity to comply with novel indications and social needs, persisting technical challenges, brand-new clinical technologies, and novel revolutions coming from academia. This "views and reviews" piece aims at outlining the advancement of oocyte vitrification from all these tightly connected perspectives.

In vitro fertilization and perinatal outcomes of patients with advanced maternal age after single frozen euploid embryo transfer: a propensity score-matched analysis of autologous and donor cycles.

OBJECTIVE: To evaluate in vitro fertilization (IVF) and perinatal outcomes of donor egg and autologous cycles in patients with advanced reproductive age after undergoing single frozen euploid embryo transfer. DESIGN: A multicenter, retrospective, cohort study. SETTING: University-affiliated and private IVF centers. PATIENT(S): Patients aged 39-46 years who underwent IVF with intracytoplasmic sperm injection and preimplantation genetic testing for aneuploidy using whole-chromosome sequencing with donor (n = 278) or autologous (n = 278) oocytes between October 2017 and October 2021. INTERVENTION(S): Single frozen euploid embryo transfer with donor or autologous euploid embryo. MAIN OUTCOME MEASURE(S): The main outcome measure was the live birth rate (LBR) after the first embryo transfer, calculated per embryo transfer. The secondary outcomes included the implantation rate, ectopic pregnancy rate, miscarriage rate, and gestational age and birth weight at the time of delivery. RESULT(S): Patients using donor or autologous oocytes had a similar likelihood of implantation (57.91% [51.87-63.78] vs. 57.19% [51.15-63.09]) and LBR (41.01% [95% confidence interval {CI}, 35.17-47.04] vs. 42.45% [95% CI, 36.56-48.49]). Furthermore, there were no significant differences in the ectopic pregnancy rate (0.72% [0.09-2.57] vs. 0.36% [0.01-1.99]), miscarriage rate (16.19% [12.06-21.05] vs. 14.39% [95% CI, 10.48-19.08]), gestational age (38.50 [38.08-38.92] vs. 39.16 [38.25-40.07] weeks), or birth weight of infants (2,982.25 [2,606.69-3,357.81] vs. 3,128.24 [2,962.30-3,294.17] kg). The univariate analysis showed no association between advanced maternal age and the LBR (relative risk, 1.03 [95% CI, 0.84-1.25]). Multivariate analysis using putative confounders for embryo competency found no associations with LBR (adjusted relative risk, 1.22 [95% CI, 0.75-1.98]). CONCLUSION(S): Patients with euploid blastocysts derived from donor or autologous oocytes did not reveal statistically significant differences in the LBR, implantation rate, ectopic pregnancy rate, miscarriage rate, duration of gestation, or infant birth weight. These findings suggest that age-related reproductive decline and/or poor IVF outcomes associated with women with advanced reproductive age undergoing IVF are heavily driven by embryonic aneuploidy.

Subcutaneous G-CSF administration improves IVF outcomes in patients with recurrent implantation failure presenting a KIR/HLA-C mismatch.

RESEARCH QUESTION: Despite advances in assisted reproductive technologies, many blastocysts are lost unexpectedly during implantation. Alterations in maternal immune tolerance towards fetal antigens may contribute to adverse IVF outcomes. The purpose of this study is to evaluate whether administering Granulocyte Colony-Stimulating Factor (G-CSF) to couples with a Human Leukocyte Antigen/Killer-Cell Immunoglobulin-Like Receptor (HLA/KIR) mismatch could positively modulate the implantation process in patients with recurrent implantation failure (RIF). A KIR/HLA-C mismatch occurs when the interaction between KIRs and HLA-C causes an inhibition of NK cells, which may result in reduced G-CSF secretion leading to impaired placentation and increased risk of miscarriage, pre-eclampsia and fetal growth restriction. DESIGN: A retrospective monocentric cohort study conducted at the IVI Clinic in Rome, including women with a history of at least two failed blastocyst transfers. Couples underwent KIR and HLA-C testing. Couples with a KIR/HLA-C mismatch received G-CSF subcutaneously up to week nine of gestation. The mismatch included cases with inhibitory KIR genotypes and HLA-C2C2 females with HLA-C1C1, or C1C2 males or HLA-C1C2 females with male HLA-C2C2. The reproductive outcomes were assessed, and the logistic regression models controlled for potential confounders affecting IVF outcomes. RESULTS: 79 patients with RIF and a KIR/HLA-C mismatch were included in the study. 30 patients were administered G-CSF, and 49 received no treatment. In the univariate analysis, no statistically significant differences were reported in the reproductive outcomes after IVF between the women treated with G-CSF and the control group. However, the logistic regression analysis that controlled for confounding factors showed that patients treated with subcutaneous G-CSF had statistically significant higher ongoing-pregnancy (aOR=3.808) and live-birth (aOR=4.998) rates, and a lower miscarriage rate (aOR=0.057). No statistically significant differences were found in other reproductive outcomes. CONCLUSION: The use of subcutaneous G-CSF in patients with a KIR/HLA-C mismatch undergoing IVF may reduce miscarriage and improve live-birth rates. G-CSF may modulate NK-mediated immune mechanisms and improve trophoblast invasion and development. Randomized trials are warranted to validate these findings and enhance the chances of successful pregnancies in couples with an immunological mismatch.

Higher serum progesterone level has no negative impact on live birth rate in frozen embryo transfer.

Optimal synchronisation between the endometrium and the embryo is key to the success of frozen embryo transfers (FET). It is achieved by administering different doses of exogenous oestrogen and progesterone (P4). The negative impact of low levels of P4 on FET has been reported, but there is a lack of knowledge about which levels are most appropriate. We aimed to evaluate whether high serum P4 levels measured on FET day affect the probability of having a baby at home. This retrospective cohort study includes 7546 FET cycles performed with hormone replacement therapy (HRT) for artificial endometrial preparation. Patients were divided into three groups according to P level on FET day (ng/mL): P4 < 20(n = 6623), P4 ≥ 20-40 (n = 770) and P > 40 (n = 146). Female age was per group P4 < 20 = 38.7 ± 3.1, P ≥ 20-40 = 39.0 ± 3.0, and P4 > 40 = 38.1 ± 2.9 years old (p = 0.53). The group with the highest progesterone levels found lower ongoing pregnancy rates without statistical significance (56.3 % (P4 < 20) vs 56.8 % (P4 ≥ 20-<40) vs 51.4 % (P4 > 40); p = 0.5). Miscarriage rate was also higher, although not significantly: 16.2 % (P4 < 20) vs 15.0 % (P4 ≥ 20-<40) vs 18.0 % (P4 > 40) (p = 0.6). These findings were explored with an adjusted analysis. A higher, but not significant, odds of miscarriage was observed when P4 > 40 ng/ml, aOR = 1.14 (0.75-1.74) (p = 0.55) whereas no such association was found with P4 ≥ 20-40 ng/ml (aOR = 0.92 (0.74-1.15) (p = 0.46)). The probability of livebirth is similar when the patient was P4 > 40 (aOR = 0.77 (0.51-1.15) (p = 0.20)) than when P4 ≥ 20-<40 (aOR = 0.94 (0.79-1.11) (p = 0.47). In conclusion, women with elevated serum P4 levels on the day of FET after HRT do not find their probability of live birth impaired.

Female obesity: short- and long-term consequences on the offspring.

The worldwide prevalence of obesity has risen over the past few decades and women are currently more likely than ever to enter pregnancy obese. Pre-pregnancy obesity and excessive gestational weight gain increase miscarriage rates and obstetric and neonatal complications, which result in a lower healthy live birth rate. In addition to its negative consequences for the mother, obesity has been shown to be an important risk factor for chronic illnesses, such as cardiovascular disease, metabolic syndrome and type 2 diabetes in the adolescence and adulthood of the offspring. Moreover, maternal obesity causes psychological problems, physical disabilities and higher healthcare costs. Fetal programming of metabolic function induced by obesity, through physiological and/or epigenetic mechanisms, may have an intergenerational effect and could, thus, perpetuate obesity in the next generation. In order to break this vicious circle and avoid serious short- and long-term negative outcomes for both mothers and fetuses, the prevention and adequate management of obesity and gestational weight gain are essential.

Obesity Affects Endometrial Receptivity by Displacing the Window of Implantation.

Our aim was to determine prospectively whether increased body mass index (BMI) affects endometrial receptivity through displacement of the window of implantation (dWOI) using the endometrial receptivity analysis (ERA), and whether this effect is BMI-dependent. We recruited a population of 170 infertile women with a normal uterus and no clinical history of recurrent miscarriage or implantation failure. These women were divided into four groups according to BMI: normal weight (18.5-24.9 kg/m2; n = 44), overweight (25-29.9 kg/m2; n = 29), class I obese (30.0-34.9 kg/m2; n = 54), and class II and III obese (> 35 kg/m2; n = 43). We also assigned the patients to one of two larger BMI cohorts: non-obese (normal weight and overweight; n = 73) and obese (class I, II, and III obese; n = 97). We compared analytical and clinical data and dWOI in these categories, finding significant metabolic differences in glycemia, TSH, insulin, HDL cholesterol, LDL cholesterol, triglycerides, and systolic and diastolic blood pressure among the different BMI groups. One-day dWOI increased significantly with BMI, and significant differences were observed in the non-obese versus obese categories (9.7% vs 25.3 %, respectively (p = 0.02)). dWOI was most pronounced in patients with class II-III obesity. In addition, displacement was longer as BMI increased since ERA revealed a higher proportion of displacements of 1 day than of 12 h and showed they were predominantly pre-receptive. In conclusion, obesity has a negative effect on endometrial receptivity through delaying of the WOI, which increases in function of BMI as well as the metabolic disturbances of the patient.

The POSEIDON Criteria and Its Measure of Success Through the Eyes of Clinicians and Embryologists.

This article represents a viewpoint on the POSEIDON criteria by a group of clinicians and embryologists. Its primary objective is to contextualize the Poseidon criteria and their metric of success for the relevant Frontiers Research Topic "POSEIDON's Stratification of Low Prognosis Patients in ART: The WHY, the WHAT, and the HOW". "Low prognosis" relates with reduced oocyte number, which can be associated with low or sometimes a normal ovarian reserve and is aggravated by advanced female age. These aspects will ultimately affect the number of embryos generated and consequently, the cumulative live birth rate. The novel system relies on female age, ovarian reserve markers, ovarian sensitivity to exogenous gonadotropin, and the number of oocytes retrieved, which will both identify the patients with low prognosis and stratify such patients into one of four groups of women with "expected" or "unexpected" impaired ovarian response to exogenous gonadotropin stimulation. Furthermore, the POSEIDON group introduced a new measure of clinical success in ART, namely, the ability to retrieve the number of oocytes needed to obtain at least one euploid blastocyst for transfer in each patient. Using the POSEIDON criteria, the clinician can firstly identify and classify patients who have low prognosis in ART, and secondly, aim at designing an individualized treatment plan to maximize the chances of achieving the POSEIDON measure of success in each of the four low prognosis groups. The novel POSEIDON classification system is anticipated to improve counseling and management of low prognosis patients undergoing ART, with an expected positive effect on reproductive success and a reduction in the time to live birth.