P-772 Three-dimensional folliculometry (SonoAVC) provides a better estimation of total and mature oocyte yields compared to conventional two-dimensional assessment in oocyte donors: a prospective, cohort study
Authors: Reshota N , Bodri D , Rogel S , Cañada I , García M , Aizpurua J 
Published: June 2023

Abstract

Study question
Does three-dimensional folliculometry (using SonoAVC) provide a better estimate of the number of retrieved and mature oocytes in egg donors compared to conventional two-dimensional assessment?

Summary answer
Three-dimensional folliculometry was superior to the two-dimensional ultrasound assessment and provided an excellent prediction (+/-20%) of total oocyte yield in almost two-thirds of participants.

What is known already
When used for monitoring ovarian stimulation, 3-D folliculometry has been shown to reduce inter-, and intra-observer variability and was significantly faster than conventional, two-dimensional ultrasound assessment (Vandekerchove F, 2014, Rei 2019). Although so far, no study has demonstrated improved clinical outcomes in IVF patients, the impact of 3D-folliculometry was not yet thoroughly evaluated in oocyte donation programmes, where expected total and mature oocyte yield is a crucial variable.

Study design, size, duration
Ninety-one consecutive oocyte donors were prospectively evaluated using three-dimensional folliculometry with SonoAVC software (E8, General Electric). A single operator (DB) performed all 3D ultrasound measurements immediately before starting oocyte retrieval and the oocyte retrieval procedure too. Two-dimensional measurement of follicles (average of two perpendicular diameters) was performed two days before egg retrieval by a single operator (NR) (Mindray DC7). Oocyte donors’ age (26.2±3.7 years), BMI (23.8±3.9), and baseline AMH (4.6±2.3 ng/mL) were also registered.

Participants/materials, setting, methods
Voluntary, anonymous oocyte donors were stimulated with a GnRH antagonist protocol and triggered with a GnRH agonist. Good, moderate, and poor prediction by ultrasound were defined as an oocyte/follicle count ratio of 80-120% (+/-0-20%), 60-79% or 121-140% (+/- 21-40%), and less than 60% or more than 140% (+/- more than 40%), respectively. For total oocyte yield, a threshold of all follicles 13 mm or above was used, both for the two- and three-dimensional assessment.

Main results and the role of chance
The number of total and mature oocytes retrieved was 22.2±9.4 and 19.0±8.3, respectively with an excellent average maturity rate of 86% (range: 44-100%). No donors were excluded from the study due to suboptimal visualization of ovaries with SonoAVC. For total oocyte yield; good, moderate, and poor prediction was achieved in 37, 44, 19% of donors with two-dimensional and in 63, 29, 8% of participants with three-dimensional folliculometry, respectively (p = 0.002). Significant underestimation of total oocyte yield (defined as more than 6 „missing” total oocytes) was less frequent with 3D assessment (12 versus 25% p = 0.022). For total oocyte yield, linear regression analysis showed a significantly higher r-square value with three-dimensional assessment (0.676 vs 0.278). For mature oocytes, the prediction was less precise than for total oocyte yield. Good, moderate, and poor prediction was achieved in 40, 30, 30% of donors with two-dimensional and in 55, 30, 15% of participants with three-dimensional folliculometry, respectively (p = 0.031). For mature oocytes, linear regression analysis showed a significantly higher r-square value with three-dimensional assessment (0.664 vs 0.282). The best SonoAVC threshold to predict total and mature oocyte yields was the sum of all follicles equal or above 13 mm and total follicle count between 24-13 mm, respectively.

Limitations, reasons for caution
Due to practical reasons, three- and two-dimensional measurements were not performed on the same day or with the same ultrasound equipment. In future studies, 3D-folliculometry could be used at the egg collection scheduling (2-3 days before the procedure) so that predictive information on oocyte yield would be available earlier.

Wider implications of the findings
Apart from reducing inter-observer variability and diminishing discomfort (faster examination time), 3D-folliculometry might have a significant role in the management of OD programmes by improving the prediction of total/mature oocyte yields. 3D-measurements performed before the procedure could also play a role in the quality control of the egg collection procedure.

Trial registration number
Not applicable