Researchers have recently published findings of a retrospective study comparing natural cycle IVF (NC-IVF) and conventional IVF (cIVF) treatments to investigate the impact of high-dose gonadotrophin stimulation on oocyte and early-stage embryo development. The study analyzed 616 NC-IVF and 167 cIVF cycles, involving a total of 2110 oocytes.

In NC-IVF cycles, only human chorionic gonadotrophin was used to trigger ovulation. In contrast, cIVF cycles employed antagonist protocols, with daily doses of 150-300 IU of human menopausal gonadotrophins. The primary outcomes of the study were the presence of mature (metaphase II) eggs, zygotes, and embryos with good morphology two days after egg retrieval.

The study found that the mature oocyte rate, the zygote rate per oocyte retrieved, and the zygote rate per mature oocyte were all significantly higher in NC-IVF cycles than in cIVF cycles. However, no difference was observed in the percentage of zygotes that developed into cleavage-stage embryos. For transferred embryos the likelihood of having a good embryo morphology with four blastomeres and a fragmentation of <10% in cleavage-stage embryos was also higher in NC-IVF cycles.

These results suggest that high-dose gonadotrophin stimulation affects oocyte maturity, fertilization, and morphology of cleavage-stage embryos in fresh IVF cycles. Despite the retrospective nature of the study and the inclusion of several treatment cycles per participant, the research offers valuable insights into the impact of gonadotrophin stimulation on oocyte and embryo development.

It is important to note that while the study found differences in oocyte and embryo parameters, no significant differences were detected in pregnancy and live birth rates. Additional research is needed to determine whether the observed effects on oocyte and embryo development also impact pregnancy and live birth outcomes.

This study contributes to the growing body of evidence suggesting that high-dose exogenous gonadotrophins may affect oocyte and embryo quality, with potential implications for IVF treatments, particularly for poor and very poor responders. Further research is needed to evaluate the potential impact of these findings on pregnancy and live birth rates, as well as to explore alternative treatment strategies for patients with diminished ovarian reserve.

Sources and References

Does high-dose gonadotrophin stimulation have an effect on oocyte and early-stage embryo development?
Reproductive BioMedicine Online

https://www.rbmojournal.com/article/S1472-6483(22)00815-X/fulltext