Retraction Statement

Objectives: Luteinizing hormone (LH) plays a key role in normal follicular development and oocyte maturation in controlled ovarian stimulation. LH stimulates the proliferation and differentiation of theca cells for the secretion of androgens, synergistically increasing estrogen production. This study aimed to investigate the effects of low LH concentrations on oocyte retrieval, fertilization, and embryo development in patients undergoing in vitro fertilization/intracytoplasmic sperm injection. Design: We prospectively (ClinicalTrials ID: NCT05755529) analyzed patients undergoing in vitro fertilization/intracytoplasmic sperm injection, subdividing them into three groups according to their age. Serum LH levels were evaluated on day 3, during stimulation (day 10) and before ovulation induction (day 12). Participants/Materials, Setting, Methods: Forty-three consecutive women were scheduled for IVF and received ovarian stimulation with follitropin alfa (Gonal F, Merck Serono, Germany) and ganirelix (Fyremaldel, Sun Pharma, Italy). Statistical analysis was performed with InStat 3.10, GraphPad software, San Diego, CA, USA. Normal distribution was tested by the Shapiro-Wilk test. Continuous variables were expressed as the mean and standard deviation. Categorical variables are expressed as frequencies and percentages. Results: Our data analysis suggests that serum LH levels progressively decrease during controlled ovarian stimulation, and this effect is more evident in the early phase of this procedure. From this perspective, circulating LH levels may significantly decrease during the late follicular phase due to the negative feedback of ovarian hormones from multiple follicular developments or after the suppressive effects of gonadotropin-releasing hormone antagonists. Limitations: Although our study confirms that exogenous LH can be considered a strategy in women with reduced LH levels during ovarian stimulation to improve oocyte quality and reproductive outcome, the generalizability of the results is limited by the low number of participants enrolled. Conclusions: Exogenous LH may be considered a strategy in women with a decrease in LH levels during ovarian stimulation to improve oocyte quality and reproductive outcome.

Effect of follicular size on oocyte retrieval, fertilization, cleavage, and embryo quality in in vitro fertilization cycles: a 6-year data collection

Effect of Oxidative Stress in Follicular Fluid and Serum on the Outcome of Assisted Reproductive Procedures

Study question What should be the optimal time interval which elapses between oocyte retrieval and denudation followed by ICSI , for optimal results in ART cycles ? Summary answer Our study suggests that an optimum interval between oocyte retrieval and oocyte denudation followed by ICSI, leads to better results in ART cycles. What is known already It is widely accepted that the best timing for OPU is 34–39 hours after ovulation trigger. Some studies suggest that preincubation time before ICSI can be beneficial when it comes to fertilization and pregnancy rates while late ICSI (fertilization) may have negative results due to oocyte ageing. Other studies claim that there is no significant difference in ART results when ICSI is performed between 2–6 hours post Oocyte-Retrieval (OR) . Few studies state that 1–3 hours of COC-culture prior to denudation and oocyte injection is better as far as fertilization , embryo quality and improved oocyte cytoplasmic maturity is concerned. Study design, size, duration RCT of 234 ICSI cycles was carried out between 2017–2019. Patients were divided into two groups-: A- Early denudation with ICSI and B- Late denudation with ICSI.Both the groups were comparable in terms of female age, number of oocytes, day of transfer, number of embryos transferred and embryo quality. Fresh or frozen embryos were transferred , which were always derived from the same stimulation cycle. Exclusion criteria were : Severe male factor / TESA / PESA. Participants/materials, setting, methods 234 ICSI cycles with similar ovarian stimulation protocols were analyzed as per time range between triggering, OPU, denudation and ICSI. Patients were divided into two groups: A- Early denudation (1–2 hours after OPU) with ICSI (1–2 hours after denudation) and B- Late denudation (4–6 hours after Oocyte-Retrieval ) with ICSI (1–2 hours after denudation).Primary outcomes were oocyte maturation and fertilization rates and secondary outcomes were clinical pregnancy rate and abortion rates. Main results and the role of chance In group B ( Late denudation and ICSI), the mean fertilization rate was 67% and the Clinical Pregnancy rate was 46%. This was better than the mean fertilization rate of 56% and clinical pregnancy rate of 39% observed in group A ( Early denudation and ICSI). However the difference was not statistically significant. Therefore, ideal maturation rates were observed when denudation ( followed by ICSI ) was delayed and done 4–6 hours after Oocyte-Retrieval. In ICSI cycles in ART , ovarian stimulation is used to induce the simultaneous growth of multiple follicles, followed by final maturation and ovulation triggering with exogenous hCG. or GnRH-Agonist or both. Generally, oocyte retrieval (OR) is performed 34 - 36h later. In addition, 2–4 hours in culture of the cumulus oocyte complexes (COC) prior to oocyte injection is believed beneficial for fertilization and embryo quality, probably due to improved oocyte cytoplasmic maturity. However, in large ART centers with high workloads, following such definite time intervals is frequently very difficult. Limitations, reasons for caution In large busy centers , maintaining meticulous time intervals is difficult . As our study numbers are small, larger multicentric trials are required in order to confirm our findings and to provide more robust data . This data cannot be applied to IVM, TESE / PESE and severe male-factor infertility. Wider implications of the findings: To achieve a successful fertilization, both nuclear and cytoplasmic maturity are required. Our Study indicates that a slight delay in denudation following Oocyte-Retrieval , will yield a higher number of good quality oocytes. A higher success rate can also be expected due to more number of embryos available for transfer. Trial registration number Not applicable

Study question Is the cumulative live birth rate (CLBR) in oocyte donation cycles with frozen eggs comparable when pituitary suppression is performed with MPA versus GnRH antagonist? Summary answer The likelihood of achieving a live birth in oocyte donation cycles using vitrified eggs is higher when MAP is used compared to GnRH antagonist. What is known already Elevated estrogen levels during IVF can trigger a premature LH surge, affecting outcomes. GnRH agonists and later antagonists were used to counter this, offering benefits like shorter cycles but requiring daily injections, cold storage, and incurring higher costs. Progestins, such as MPA, emerged as alternatives, showing comparable success in oocyte retrieval and embryo quality. However, research has primarily focused on fresh oocyte donation cycles. This study evaluates MPA protocols in oocyte donation using vitrified eggs, aiming to determine their impact on cumulative live birth rates (CLBR) compared to GnRH antagonists, addressing a critical gap in current knowledge. Study design, size, duration This multicenter retrospective observational study analyzed oocyte donation cycles conducted between January 2017 and October 2022. The study included recipients with ≥8 warmed metaphase II oocytes fertilized with autologous sperm > 5 mill/mL, with subsequent embryo culture extended to blastocyst stage. Cycles meeting these criteria were classified based on the protocol used for LH surge suppression, either GnRH antagonists or MPA. All oocytes were vitrified and warmed using the standardized Kitazato protocol. Participants/materials, setting, methods A total of 669 recipients received oocytes from stimulation protocols using GnRH antagonists, while 452 received oocytes from protocols employing MPA. Main outcome measured was CLBR per number of embryos transferred. Kaplan Meier curves were used to present CLBR per embryo transferred and Cox regression was performed to calculate hazard ratios (HR). Additionally, oocyte survival rate, fertilization rate and blastulation rate were compared between groups for enhance understanding of the clinical significance of the results. Main results and the role of chance Oocyte survival rate (87.51%, CI 95% 86.48 to 88.53 in antagonist group vs. 90.66%, CI 95% 89.55 to 91.76 in MPA group, p < 0.001), fertilization rate (75.22%, CI 95% 74.01 to 76.43 in antagonist group vs. 77.91%, CI 95% 76.49 to 79.33 in MPA group, p = 0.005) and blastulation rate (41.71%, CI 95% 39.80 to 43.62 in antagonist group vs. 50.33%, CI 95% 48.06 to 52.59 in MPA group, p < 0.001) were higher in MPA group. The probability to achieve one live birth after transferring one embryo was 48.12% (CI 95% 43.81% to 52.10) in antagonist group and 61.81% (CI 95% 56.72 to 66.30) in MPA group. CLBR was statistically higher when oocytes were obtained after donor stimulation with MPA protocol (HR 1.298, CI 95% 1.120 to 1.504, p < 0.001). Limitations, reasons for caution The retrospective design of this study should be considered. Despite being a large sample size for progesterone-primed ovarian stimulation in donors whose oocytes were vitrified, the number of recipients included could be considered low. Moreover, the findings are applicable only when medroxyprogesterone acetate (MPA) is used as progestin. Wider implications of the findings MPA may enhance clinical outcomes in oocyte cryopreservation. Its lower cost and oral administration make it a cost-effective strategy to improve the efficiency of oocyte banking. These findings support the use of the MPA protocol, particularly for fertility preservation in women under 35 years old. Trial registration number No

Anaesthesia for assisted conception

Effect of injected spermatozoa morphology on the outcome of intracytoplasmic sperm injection in humans

Last chance before egg donation: modified natural cycle in vitro fertilization in poor responder patients; the role of follicle diameter on the day of hCG administration in order to improve results

Follicular fluid levels of anti-Mullerian hormone as a predictor of oocyte maturation, fertilization rate, and embryonic development in patients with polycystic ovary syndrome

Assessment of the optimal number of follicular flushes on retrieval rate and quality of oocytes in mono-follicular in-vitro fertilization (IVF) cycles. A retrospective analysis of 246 oocyte pick-up procedures in mono-follicular IVF cycles of 226 poor responder women was performed. The primary endpoint was oocyte retrieval rate in the initial aspirate versus subsequent flushing episodes. The secondary endpoints were oocyte maturity, fertilization rates and embryo cleavage. The procedure was successful in 187 cycles (76%), of which 160 metaphase-II oocytes were retrieved. Retrieval rates were similar for natural and modified natural cycles (p=0.595). The initial aspirate provided 54% of the total yield and the rest was obtained from up to four episodes of flushing. Follicular flushing increased oocyte recovery rate from 41.1% to 76%. None of the oocytes retrieved after three flushes fertilized. Oocyte maturity, fertilization and embryo cleavage rates were comparable for oocytes from the initial aspirate and one or two episodes of flushing. Oocytes obtained after the third flushing episode developed into poor quality embryos. Flushing confers a benefit for oocyte recover rates in mono-follicular IVF cycles in poor responder women. However, more than three attempts at flushing were not associated with good outcome.

“Rescue” Intracytoplasmic Sperm Injection (ICSI) Can Result in Acceptable Pregnancy Rates in In Vitro Fertilization (IVF) Patients with Complete Fertilization Failure

To determine (a) the correlation between follicular sizes, oocyte maturity, normal fertilization rate, cleavage and embryo quality; and (b) to establish whether oocytes recovered with or without follicular flushing have different developmental competence. Prospective observational study. Academic medical center. Forty nine cycles (37 ICSI and 12 IVF). Measurement of 360 follicular diameters on the day of egg retrieval and classification into three groups Group A (mean diameter 12-14.5mm.), group B (mean diameter 15-18mm.) and group C (diameter >18.5mm.). Correlation between follicular size at the time of retrieval and oocyte maturity, fertilization and cleavage rate in 226 oocytes (163 ICSI and 63 IVF). Developmental competence of oocytes retrieved with flushing versus non flushing. Almost all (99%) of the oocytes recovered from follicles of group C were in metaphase II as opposed to 80% in group A and 81% in group B (p < 0.01). Overall there was a progressive and significant increase in fertilization rates from group A follicles to group C (47% vs. 67%, p 0.05). Overall 53% of oocytes retrieved from group A follicles showed either no fertilization or abnormal fertilization versus 27% in group C (p 0.05). The oocyte recovery rate with follicular flushing improved from group A to group B and to group C follicles (65% vs. 49% vs.37% respectively p < 0.01). There were no differences in rates of immature oocyte, fertilization, abnormal or not fertilization and cleavage. The results of this study shows that: a) Follicles larger than 18mm at retrieval have consistently mature oocytes with a higher rate of fertilization; b) Small size follicles are still capable of containing mature oocytes, but their rate of abnormal or no fertilization is high; c) Oocytes recovered with flushing are still able to produce embryos with full developmental competence.

Ultrasonographic assessment of endometrial receptivity at embryo transfer in an in vitro maturation of oocyte program

Background: The impact of thyroid disorders on in vitro outcomes of assisted reproductive technology (ART) remains controversial. Therefore, the aim of our study was to investigate whether thyroid peroxidase antibodies (TPO-Abs)/thyroid autoimmunity (TAI) or thyroid function (serum thyrotropin [TSH])/subclinical hypothyroidism are associated with an altered number of oocyte retrieval (NOR), fertilization rate (FR), and embryo quality (EQ). Methods: Cross-sectional study in 279 women in a single center, comprising 297 cycles and 1168 embryos. In vitro data (NOR, FR, and EQ) were documented in two groups; one according to thyroid function in women without TAI (TSH ≤2.5 and >2.5 mIU/L) and one according to the presence/absence of TAI (determined by TPO-Abs). EQ was evaluated according to international criteria and classified as excellent/good and poor. Women treated with levothyroxine (LT4) were excluded. Furthermore, the impact of thyroid parameters on outcomes, normal NOR (>6 or 8) and high FR (>60%), was verified in a multivariable logistic regression model. Results: In women without TAI, 27% had TSH levels >2.5 mIU/L, the prevalence of TAI was 8%, and overall, 6% of women had TSH levels >4.2 mIU/L. NOR, FR, and EQ were comparable between study groups. In the regression analysis, women aged ≥30 years and receiving a high ovarian stimulation dosage (>2300 IU/cycle) had lower rates of normal NOR (odds ratio [OR] 0.18 [95% confidence interval, CI 0.04-0.72]; p = 0.016 and OR 0.17 [CI 0.06-0.48]; p < 0.001, respectively). Conclusions: Our results do not suggest an impact of thyroid antibodies/autoimmunity and (dys)function on ART in vitro outcomes.

Objective:Assessment of the optimal number of follicular flushes on retrieval rate and quality of oocytes in mono-follicular in-vitro fertilization (IVF) cycles.Material and Methods:A retrospective analysis of 246 oocyte pick-up procedures in mono-follicular IVF cycles of 226 poor responder women was performed. The primary endpoint was oocyte retrieval rate in the initial aspirate versus subsequent flushing episodes. The secondary endpoints were oocyte maturity, fertilization rates and embryo cleavage.Results:The procedure was successful in 187 cycles (76%), of which 160 metaphase-II oocytes were retrieved. Retrieval rates were similar for natural and modified natural cycles (p=0.595). The initial aspirate provided 54% of the total yield and the rest was obtained from up to four episodes of flushing. Follicular flushing increased oocyte recovery rate from 41.1% to 76%. None of the oocytes retrieved after three flushes fertilized. Oocyte maturity, fertilization and embryo cleavage rates were comparable for oocytes from the initial aspirate and one or two episodes of flushing. Oocytes obtained after the third flushing episode developed into poor quality embryos.Conclusion:Flushing confers a benefit for oocyte recover rates in mono-follicular IVF cycles in poor responder women. However, more than three attempts at flushing were not associated with good outcome.