Stimulated cycle versus artificial cycle for frozen embryo transfer in patients with polycystic ovary syndrome: a Meta-analysis.

PURPOSE: Our aim is to conduct a meta-analysis comparing clinical outcomes between the mild ovarian stimulation cycle versus an artificial cycle (AC) for frozen embryo transfer (FET) in patients with polycystic ovary syndrome (PCOS). METHODS: We systematically searched the databases of PubMed, EMBASE and the Cochrane Library from inception to January 2020. The outcomes were live birth rate (LBR), ongoing pregnancy rate (OPR), clinical pregnancy rate (CPR), embryo implantation rate (IR) and miscarriage rate (MR). The mild ovarian stimulation cycle and AC were compared according to risk ratios and 95% confidence intervals using a fixed or random effects model. RESULTS: Four retrospective studies describing the clinical outcomes were included. We found no significant difference in LBR, OPR, CPR, IR or MR between the mild ovarian stimulation cycle and AC protocols, whereas a lower MR was found for the letrozole-stimulated cycle than the AC. CONCLUSIONS: The letrozole-stimulated cycle for endometrial preparation in PCOS patients undergoing FET may lower the MR more than the AC. PCOS patients using the mild ovarian stimulation cycle for endometrial preparation undergoing FET had similar LBR, OPR, CPR and IR compared with the AC. The letrozole-stimulated protocol may be a reasonable choice for endometrial preparation before FET for women with PCOS.

Exposure to podophyllotoxin inhibits oocyte meiosis by disturbing meiotic spindle formation.

Podophyllotoxin is used as medical cream which is widely applied to genital warts and molluscum contagiosum. Although previous study showed that podophyllotoxin had minimal toxicity, it was forbidden to use during pregnancy since it might be toxic to the embryos. In present study we used mouse as the model and tried to examine whether podophyllotoxin exposure was toxic to oocyte maturation, which further affected embryo development. Our results showed that podophyllotoxin exposure inhibited mouse oocyte maturation, showing with the failure of polar body extrusion, and the inhibitory effects of podophyllotoxin on oocytes was dose-depended. Further studies showed that the meiotic spindle formation was disturbed, the chromosomes were misaligned and the fluorescence signal of microtubule was decreased, indicating that podophyllotoxin may affect microtubule dynamics for spindle organization. Moreover, the oocytes which reached metaphase II under podophyllotoxin exposure also showed aberrant spindle morphology and chromosome misalignment, and the embryos generated from these oocytes showed low developmental competence. We also found that the localization of p44/42 MAPK and gamma-tubulin was disrupted, which further confirmed the effects of podophyllotoxin on meiotic spindle formation. In all, our results indicated that podophyllotoxin exposure could affect mouse oocyte maturation by disturbing microtubule dynamics and meiotic spindle formation.

[Recurrent implantation failure: gamete and embryo factors].

Despite the immense achievement in the field of IVF in recent years, many patients still suffer from recurrent implantation failure. Therefore, much attention has been drawn to its etiology and treatment. Chromosomal abnormality, sperm DNA damage, zona hardening, and inappropriate culture conditions are important factors that lead to recurrent implantation failure. Results of studies suggest that preimplantation genetic screening does not improve the rate of implantation or live birth. Comparative genomic hybridization array and single nucleotide polymorphism array could offer a more comprehensive screening of chromosomes. Assisted hatching may help to solve the problem of zona hardening in some situations. Co-culture and blastocyst transfer could be conducive to the improvement of the rates of implantation and pregnancy. Cytoplasmic transfer may give a solution to ooplasmic composition anomalies.

[Comparison of Alarelin and Triptorelin in the long-protocol ovulation induction in in vitro fertilization and embryo transfer].

OBJECTIVE: To compare the pituitary down-regulatory effects of the two gonadotropin-releasing hormone agonists Alarelin and Triptorelin in the long protocol of ovulation induction in in vitro fertilization and embryo transfer (IVF-ET). METHODS: We included in this study 122 patients aged 24-39 years treated by IVF-ET for secondary infertility, with 10-20 pre-antral follicles and obstruction of the fallopian tube. Seventy-eight of them received Alarelin, and the other 44 Triptorelin. Comparative analyses were made on the pituitary down-regulatory effects of the two gonadotropin-releasing hormone agonists and the clinical outcomes of IVF-ET. RESULTS: No premature LH surge and ovulation, nor severe hyperovarian stimulation syndrome was found in either group. There were no significant differences between the two groups in the mean dose and duration of gonodatropin treatment, the numbers of oocytes retrieved, mature oocytes and top-quality embryos, and the rates of 2PN, multi-sperm fertilization, cleavage, embryo transfer, embryo implantation, clinical pregnancy and early miscarriage (P > 0.05), but the rate of cancelled cycles was significantly higher in the Triptorelin than in the Alarelin group (P < 0.05). CONCLUSION: Alarelin and Triptorelin can achieve similar pituitary down-regulatory effects and clinical outcomes in IVF-ET when used in the long protocol of ovulation induction.