Cumulus assessment by three-dimensional ultrasound for in vitro fertilization

To correlate the appearances of intrafollicular cumulus-like structures using three-dimensional (3D) ultrasound technology with the recovery of mature oocytes.

A prospective, observational study using 3D ultrasound examination was performed in 50 women undergoing in vitro fertilization (IVF) after ovarian stimulation. Examination was performed on the day of human chorionic gonadotropin (hCG)-ovulation induction. Estradiol-17-beta (E2) levels were measured on the same day. The ovaries were examined for the presence of cumuli in all follicles greater than 15 mm in diameter. Only cumuli demonstrable in all three planes, or in a computer-animated 3D reconstruction, were recorded as 'visible'. The number, maturity, and fertilization rate of retrieved oocytes were compared with the pre-ovulatory assessment of cumuli by 3D ultrasound.

Correlation coefficients (Pearson) between the variables were calculated and stepwise regression analyses performed.

A total of 262 cumuli were visualized within 318 follicles from which 296 mature oocytes were retrieved and 218 fertilized. There was a significant correlation between the number of detected cumuli and the number of retrieved oocytes (r2 = 0.83; P < 0.0001), mature oocytes (r2 = 0.78; P < 0.0001), and the number of the fertilized oocytes (r2 = 0.65; P < 0.0001). There was a marked correlation between E2 and the number of follicles and the number of fertilized oocytes.

Cumulus visualization by 3D ultrasound appears to be an indicator for mature oocytes and successful fertilization. Follicles in which the cumulus cannot be visualized in all three planes are unlikely to contain mature oocytes or oocytes in which fertilization is achieved.