P–628 Predicting oocyte yield in patients with diminished ovarian reserve using basal antral follicle count

Abstract

Abstract Study question Is basal antral follicle count (bAFC) taken on day 1 to 3 of stimulation a useful predictor of oocyte yield in that cycle, in women with diminished ovarian reserve (DOR)? Summary answer Basal AFC has moderate correlation with final oocyte yield. A median 75% of the antral follicle count is collected as oocytes. What is known already The current theory of folliculogenesis suggests that all follicles available for recruitment are visible on ultrasound in the ovary at the point when ovarian stimulation is applied. This implies a tight correlation between the AFC on day 1–3 of a stimulation cycle (bAFC) and the eventual number of follicles collected. We hypothesise that in women with diminished ovarian reserve who receive maximum stimulation basal AFC would be a useful predictor of final oocyte yield in that cycle. Study design, size, duration This was a prospective single centre, observational study in a tertiary referral hospital in London. 125 women with DOR underwent controlled ovarian stimulation between December 2018 and January 2021. Participants/materials, setting, methods All study participants were given an antagonist cycle with a starting stimulation dose of 450iu and remained on the same dose throughout their treatment. We assessed the correlation between bAFC taken on day 1–3 of the stimulation cycle and the total number of oocytes collected. Main results and the role of chance A total of 150 treatment cycles were included in the analysis. The median age was 37 (IQR 35 – 39). The median AMH was 6.0 (IQR 4.4 – 8.9) and the median FSH was 7.6 (IQR 5.7 – 9.4). The median bAFC at the start was 9 (IQR 6 – 11). The median total stimulation dose was 4050iu (IQR 4050 – 4500). The median oestradiol on day of trigger was 5906 (IQR 4166 – 7397) and median number of oocytes collected was 7 (IQR 5 – 9). There was a moderate correlation between bAFC and the number of oocytes collected (r = 0.549, p = 0.005). The median ratio of oocytes collected over the number of antral follicles observed at the start was 72.7% (IQR 58.3 – 100). Limitations, reasons for caution We have standardised approach to AFC determination and have previously shown that AFC inter and intra-observer variability in our unit is low. Nevertheless, our study involved multiple operators for AFC determination which may introduce variability. Further variability may have been introduced at egg collection by varying technique. Wider implications of the findings: Studies of antagonist protocol in good prognosis patients suggest poor correlation between basal AFC and oocyte yield. In contrast, our study shows that in a population of women with DOR basal AFC provides useful information which can be used to counsel women around the expected oocyte yield of their cycle. Trial registration number Not applicable