The antral follicle count (AFC) correlates with metaphase II oocytes and ART cycle outcome: an update

Abstract

Objective: We reported the antral follicles count (AFC) correlated with Metaphase II (MII) oocytes obtained in that cycle among an initial cohort of 80 patients. Since then, we have accumulated data on an additional 120 patients. This update correlated the AFC with MII oocytes recovered in that cycle and with the cycle outcome among a large cohort. Design: Prospective, observational study in a private practice setting. Materials/Methods: Infertile couples undergoing treatment with ART (n = 200) had a baseline ultrasound evaluation prior to ovarian stimulation to exclude cyst formation. Recombinant gonadotropins were used for ovarian stimulation after pituitary desensitization with a GnRHa in a long protocol. Ovulation was triggered with hCG when 2 follicles measured ≥18mm in diameter and half the remainder were ≥15mm. Oocytes were recovered transvaginally under ultrasound guidance 34–35 hours later. Antral follicles visualized at baseline evaluation were counted and correlated with the MII oocytes retrieved in that cycle using a Pearson coefficient. Differences in rates were analyzed using Chi-square tests. Significance was set at p <0.5. Results: The mean patient age was 32 years (range: 19–44). Mean cycle day 3 FSH level was 6.8mIU/ml (range: 1.7–18). The number of antral follicles seen on baseline ultrasound (mean: 15; range: 4–35) correlated strongly with the number of MII oocytes recovered in that cycle (mean: 14; range: 2–47)(r = 0.80; p <0.001), while other predictors of response to stimulation, (such as follicles number ≥15mm in diameter or peak Estradiol level), were less predictive of response. Overall pregnancy and implantation rates were 41% and 24%, respectively. Patients with an AFC ≥20 had significantly higher pregnancy and implantation rates (67% and 32%) than patients with an AFC <10 (24% and 18%) or AFC=10–19 (36 and 22%). Conclusions: Assessment of antral follicle number on baseline ultrasound prior to ovarian stimulation for ART is easy to perform and correlates well with the number of mature oocytes that will be recovered in that cycle. The AFC may be a better predictor of ovarian response than traditional indicators of ovarian reserve, and could be used alone or in conjunction with these parameters to titrate medication dosages, and determine the optimal number of embryos to transfer. Many factors influence pregnancy beyond the number of mature oocytes. However, routinely canceling “poor responders” cannot be recommended, since 24% of patients with an AFC <10 developed an ongoing gestation. Supported by: None.