Comparative Analysis of Controlled Ovarian Hyperstimulation and Modified Natural Cycle Protocols on Gene Expression and Quality of Oocytes, Zygotes, and Embryos in Assisted Reproductive Technology (ART)

Abstract

This study investigated the influence of two in vitro fertilization (IVF) protocols-controlled ovarian hyperstimulation (COH) and a modified natural cycle protocol-on gene expression levels (Anti-Müllerian Hormone (AMH), Anti-Müllerian Hormone Receptor Type 2 (AMHAMHR2), Follicle-Stimulating Hormone Receptor (FSHR), and Androgen Receptor (AR)) and the subsequent reproductive outcomes of assisted reproductive technology (ART). Gene expression, as well as oocyte, zygote, and embryo morphological parameters, were analyzed to evaluate the differences between the protocols. Our findings show that AMH expression was significantly associated with successful fertilization, while AMHAMHR2 expression correlated with improved embryo transfer outcomes. The modified natural cycle protocol demonstrated a higher association with the favorable gene expression profiles, particularly for AMH and AMHAMHR2, linked to successful fertilization and embryo transfer, suggesting potential advantages of minimal intervention. However, the overall quality scores for the oocytes, zygotes, and embryos were comparable between the protocols. The trend of a higher transfer success for the natural cycle, though not statistically significant, indicated potential protocol effects on the uterine environment. This study highlights the complexity of ART outcomes and suggests that incorporating gene expression markers with protocol adjustments may optimize individual ART strategies.

Keywords: assisted reproductive technology; controlled ovarian hyperstimulation; gene expression; in vitro fertilization; oocyte grade.

Figure 1

Anti-Müllerian Hormone (AMH), signaling pathway in granulosa cells. This figure shows AMH binding to its receptor Anti-Müllerian Hormone Receptor Type 2 (AMHR2) on granulosa cells, regulating folliculogenesis. Follicle-Stimulating Hormone Receptor (FSHR), and Androgen Receptor (AR) are also depicted, reflecting their roles in follicular development and hormone response. AMH modulates follicle recruitment and Follicle-Stimulating Hormone (FSH) sensitivity, essential for ovarian reserve and fertility. Created with BioRender.com.

Figure 2

Comparison of gene expression levels (ΔCt values) between antagonistic (A) COH and modified natural cycle (N) IVF protocols (significant difference, p < 0.05).

Figure 3

Comparison of gene expression levels (ΔCt values) between fertilization success outcome (successful “YES” vs. unsuccessful “NO”). Significant difference, p < 0.05 (in red).

Figure 4

Comparison of gene expression levels (ΔCt values) between embryo transfer success outcome (successful “YES” vs. unsuccessful “NO”). Significant difference, p < 0.05 (in red).