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We propose a two stages mosquito egg-larvae model with seasonality as a simplification of a four stages one. For the simplified model we characterize the dynamics in terms of the vectorial reproduction number, [Formula: see text], obtaining extinction if [Formula: see text] and convergence to a unique positive periodic orbit if [Formula: see text]. We illustrate each case with an example, by providing general conditions on the periodic coefficients for its occurrence. These examples are further developed using numerical simulations where the periodic parameters satisfy the conditions obtained. In the [Formula: see text] case, real climatic data is used for inferring the parameter behaviour. For the four stage system, using alternative oviposition rate functions, we present a result which generalizes others given for models with delays and even with diffusion to the case in which competition between the larvae is introduced. The analytical study of our initial four stages system when [Formula: see text] remains open, since we were not able to prove that in this case the system is dissipative., (© 2023. The Author(s).)

Purpose: To compare reproductive outcomes of the ROPA method (reception of oocytes from partner) to IVF with autologous oocytes. To study the impact of the absence of a genetic link between the embryo and its recipient in reproductive outcomes., Methods: Retrospective multicentric cohort study performed from January 2011 to December 2020 in 18 fertility clinics in Spain. A total of 99 ROPA (73 couples) and 2929 non-ROPA cycles (2334 couples or single patients) of women younger than 38 years old with no known female fertility disorder were included. Clinical outcomes were compared between both groups and included positive pregnancy test, clinical pregnancy, miscarriage, ectopic pregnancy, pre-term birth, live birth, weeks of gestation at birth, and newborn weight at birth., Results: No differences were found between groups in clinical outcomes. The total clinical pregnancy rates per embryo transfer were 57% and 50.2% (p = 0.15) and the live-birth rates were 46.1% and 40.9% (p = 0.14) for the ROPA and non-ROPA groups, respectively. When adjusted to age and BMI of donors and recipients, there were also no differences in live-birth rates between both groups. The cumulative live-birth rate per ROPA cycle was 73.7% and the cumulative live-birth rate per couple was 78.3%., Conclusion: Clinical outcomes following the ROPA method and IVF with autologous oocytes were found to be similar. These findings suggest no impact of the absence of genetic ties between the embryo and the uterus on reproductive treatments' outcomes. Data regarding the outcomes of the ROPA method are reassuring., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

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/m 2 ; n = 44), overweight (25-29.9 kg/m 2 ; n = 29), class I obese (30.0-34.9 kg/m 2 ; n = 54), and class II and III obese (> 35 kg/m 2 ; 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., (© 2021. Society for Reproductive Investigation.)

Purpose: Intracytroplasmatic sperm injection (ICSI) is a common procedure used to improve reproductive results, even among couples without male factor infertility. However, the evidence available is still uncertain on the possible advantages and deficiencies that this procedure may have in patients with no formal indication for ICSI., Methods: A SWOT (strengths, weaknesses, opportunities, threats) analysis examines the possible advantages and deficiencies of performing ICSI in these patients with no formal indication., Results: The evidence suggests that ICSI is not justified for non-male factor infertile couples requiring in vitro conception. One of the major strengths associated to the procedure is the virtual elimination of cases further complicated by total fertilization failure and a combination between IVF and ICSI on sibling oocytes has been advised in the literature. Greater technical difficulties, higher costs and performing an unnecessary invasive technique in some cases represent some of the weaknesses of the procedure, and questions regarding safety issues should not be ruled out., Conclusion: Despite the widespread use of ICSI in patients without a formal diagnosis of male factor infertility, evidence demonstrating its effectiveness in this population is still lacking. Additional large and well-designed randomized controlled trials are needed to clarify definitive indications for ICSI in non-male factor infertility.

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder among reproductive-aged women and the main cause of infertility due to anovulation. However, this syndrome spans the lives of women affecting them from in-utero life until death, leading to several health risks that can impair quality of life and increase morbidity and mortality rates. Fetal programming may represent the beginning of the condition characterized by hyperandrogenism and insulin resistance which leads to a series of medical consequences in adolescence, adulthood, and old age. Menstrual and fertility problems evolve into metabolic complications as age advances. An early and precise diagnosis is important for an adequate management of PCOS, especially at the extreme ends of the reproductive lifespan. However, many different phenotypes are included under the same condition, being important to look at these different phenotypes separately, as they may require different treatments and have different consequences. In this way, PCOS exhibits a great metabolic complexity and its diagnosis needs to be revised once again and adapted to recent data obtained by new technologies. According to the current medical literature, lifestyle therapy constitutes the first step in the management, especially when excess body weight is associated. Pharmacotherapy is frequently used to treat the most predominant manifestations in each age group, such as irregular menses and hirsutism in adolescence, fertility problems in adulthood, and metabolic problems and risk of cancer in old age. Close surveillance is mandatory in each stage of life to avoid health risks which may also affect the offspring, since fetal and post-natal complications seem to be increased in PCOS women.