Inability of sonography to detect imminent ovulation

Area of Science:

• Reproductive endocrinology and imaging

Background:

• Conventional transabdominal sonography has shown potential in identifying signs of imminent ovulation, such as cumulus oophorus visualization or dominant follicle wall alterations.
• The clinical utility of advanced ultrasound techniques for precise ovulation prediction remains an area of interest, particularly for assisted reproductive technologies.

Purpose of the Study:

• To evaluate the efficacy of transvaginal sonography (TVS) in providing more frequent and confident predictions of imminent ovulation compared to conventional methods.
• To assess whether specific sonographic features, including cumulus oophorus visualization and follicle wall morphology, can reliably indicate impending ovulation using TVS.

Main Methods:

• A prospective study involving 22 ovulatory menstrual cycles from 17 women (4 undergoing artificial insemination, 13 volunteers).
• Transvaginal sonography with a 7.5-MHz transducer was performed on alternate days during the periovulatory period.
• Focus on identifying the cumulus oophorus and subtle changes in the dominant follicle wall.

Main Results:

• Despite the enhanced resolution of transvaginal sonography, confident identification of the cumulus oophorus was not achieved in any monitored cycles.
• Morphologic alterations in the dominant follicle wall, indicative of imminent ovulation, were not consistently observed or reliably identifiable.
• No other specific sonographic follicular characteristic emerged as a consistent predictor of impending ovulation.

Conclusions:

• Transvaginal sonography, even with its superior imaging capabilities, does not enable confident prediction of imminent ovulation.
• The sonographic signs previously reported with transabdominal approaches are not reliably visualized or interpreted with transvaginal ultrasound for ovulation timing.