Follicular sphericity based on three-dimensional transvaginal ultrasound algorithms predicts ovarian responsiveness to in vitro fertilization.

Background: The principal indicators adopted for the assessment of follicular quality are still two-dimensional ultrasound(2D-US) imaging parameters, but these do not reflect the three-dimensional morphology of follicles. We herein aimed to explore novel parameters of ovarian follicles by three-dimensional ultrasound (3D-US) by comparing various follicles on the trigger day in gonadotropin-releasing hormone antagonist (GnRH-ant) stimulation cycles, and investigated the effects on ovarian responsiveness, oocyte and embryo quality.

Methods: This was a prospective observational study of women who commenced their first controlled ovarian stimulation (COS) cycle with a GnRH-ant protocol from March 2023 to March 2024. A total of 248 patients were included in the study and 3D-US scanning was conducted on the HCG administration day. Utilizied 3D-US measurement data were then implemented to calculate follicular sphericity. Population demographics, infertility work-up, and ultrasonographic biomarkers were employed to construct models for the prediction of ovarian responsiveness and embryo quality.

Results: The ROC analysis showed that the cut-off point for enabling follicular sphericity to exert a significant effect on MII oocyte was 0.716, and the patients were assigned to two groups: low sphericity(< 0.716) and high sphericity(≥ 0.716). Applying the Wilcoxon signed-rank test and the general linear model for univariate analysis and controlling for confounders, women in the low sphericity group achieved a higher oocyte retrieval rate, MII oocyte rate, follicular output rate (FORT), ovarian sensitivity index (OSI), and Day 3-8cell rate relative to women in the high sphericity group (adjusted β = 5.46, 5.15, 1.08, 2.39, 1.17, respectively; all P value < 0.05) in patients with normal ovarian reserve.

Conclusion: This study was based on 3D-US measurements, follicular sphericity reliably predicted oocyte and embryo quality during in vitro fertilization monitoring in patients with normal ovarian reserve. We observed that follicular sphericity served as an available ultrasound parameter, reflecting the follicular development in COS, and providing insights for adjusting gonadotropin drug regimens.

Trials registration: http://www.chictr.org.cn Identifier: ChiCTR2400085886.