A follicular volume of >0.56 cm3 at trigger is the cutoff to predict oocyte maturity: a starting point for novel volume-based triggering criteria.

OBJECTIVE: To determine the minimum follicular volume on the day of trigger that will correspond to a mature oocyte at egg retrieval by individualized follicular puncture and to calculate the mean follicular growth from ovulation induction to egg retrieval using SonoAVCfollicle. DESIGN: A prospective observational study of 53 women undergoing in vitro fertilization, in which it was possible to identify unequivocally one or more follicles at trigger and egg retrieval using three-dimensional ultrasound. SETTING: University-affiliated private in vitro fertilization center. PATIENTS: The final sample included 206 follicles from 14 oocyte donors and 39 patients. INTERVENTIONS: A three-dimensional ultrasound with SonoAVCfollicle was performed at trigger and egg retrieval. The same operator selected follicles that were identified easily on both scans and verified that they were apt to be aspirated individually. Follicles were punctured individually, recording the real aspirated volume and the maturity stage of the oocyte. MAIN OUTCOME MEASURES: The primary outcome was the relationship between follicular volume on the day of the trigger and the oocyte maturity stage. The secondary outcome was the rate of follicular growth from the day of trigger to the day of oocyte retrieval, as measured using SonoAVCfollicle. RESULTS: On the day of trigger 206, follicles were selected. Of these, 5 could not be identified on the day of oocyte retrieval, probably because of follicular rupture (mean volume: 4 cm3, range: 2-7 cm3), and in 48, an oocyte was not obtained. The relationship between follicular volume and oocyte maturity was studied in 153 follicles: 125 (82%) contained mature and 28 (18%) contained immature oocytes. Receiver operating characteristic curves showed an area under the curve value of 0.73 (95% confidence interval: 0.65-0.80). A follicular volume of >0.56 cm3 is the cutoff point, with the highest Youden index having a sensitivity of 85% and a specificity of 64% to predict oocyte maturity. The mean follicular growth from trigger to egg retrieval was 26%-50% in 53% of cases. CONCLUSION: A follicular volume of >0.56 cm3 at trigger is the cutoff point with the optimal balance between sensitivity and specificity for oocyte maturity. Follicles of >2-3 cm3 may undergo spontaneous rupture before egg retrieval. Given these findings, we propose new volume-based criteria for trigger: 70% of follicles of >0.6 cm3 and dominant follicles between 2 and 3 cm3. These findings need validation by randomized controlled trials.

Volume-based follicular output rate improves prediction of the number of mature oocytes: a prospective comparative study.

OBJECTIVE: To test whether volume-based follicular output rate (FORT-V) is superior to diameter based follicular output rate (FORT-D) in predicting the number of mature oocytes. The follicular output rate (FORT) is the ratio between preovulatory follicle count (PFC) and antral follicle count (AFC) and has been proposed as a better predictor of the ovarian response compared with AFC alone. DESIGN: A prospective observational study of 215 consecutive women (80 oocyte donors and 135 in vitro fertilization [IVF] patients) undergoing ovarian stimulation for IVF. SETTING: University affiliated private IVF center. PATIENT(S): Women undergoing ovarian stimulation between May 2018 and September 2021. INTERVENTION(S): Manual two-dimensional ultrasound and computer-generated (three-dimensional ultrasound, [3D]) AFCs were performed at baseline. During ovulation induction, follicular growth was monitored in each patient using both two-dimensional and 3D ultrasound. Preovulatory follicles were defined as those with a mean diameter of 16-22 mm. The trigger was based on the follicular volume according to our standard protocol: at least 2 follicles with a volume of >2 cc with 70% of the follicles having a volume of >0.7 cc. MAIN OUTCOME MEASURE(S): The primary outcome was the difference between FORT-V and FORT-D in their ability to predict the mature oocyte output rate. RESULT(S): In both IVF patients and oocyte donors, the computer-generated AFC was greater than the manual AFC. The FORT-V was higher than the FORT-D for both computer-generated (the difference was 35 [95% CI {confidence interval}, 32-45] in oocyte donors and 21 [95% CI, 5-46] in IVF patients) and manual FORT (the difference was 38 [95% CI, 32-45] in oocyte donors and 15 [95% CI, 3-43] in IVF patients) and was closer to the mature oocyte output rate. There was a direct correlation between the computer-generated AFC and the PFC based on volume and between PFC based on volume and the number of mature oocytes in oocyte donors and IVF patients. CONCLUSION(S): In this prospective study of 215 women, the FORT based on 3D ultrasound derived follicular volume (FORT-V) was superior to the FORT-D in determining the ovarian response in both oocyte donors and IVF patients. Moreover, our results support the non-inferiority of the computer-generated method compared with the manual method for the determination of AFC. Further studies on the role of computer-generated antral follicle characteristics may be useful in evaluating follicle stimulation regimens.