Antral follicle size in the downregulated cycle and its relation to in vitro fertilization outcome

In this study, we have attempted to relate the antral follicle size on day 3 of downregulation to the in vitro fertilization (IVF) outcome and hence test its predictive value for IVF outcome.

Teaching hospital, prospective double-blinded cohort study. The sonographer was blinded toward the patient profile whereas the follicular size on day 3 was concealed from the clinicians.

Two hundred and twenty-eight patients undergoing the long protocol programme for IVF/intracytoplasmic sperm injection at the Institution are included in this study. The antral follicle size on day 3 of the downregulated cycle was measured for all patients and, based on the size, they were divided into three groups: Group I (0-3 mm), Group II (3-6 mm), and Group III (6-9 mm), Various outcome measures taken into account were amount and number of days of gonadotropin required, basal estradiol and follicle-stimulating hormone (FSH) level, zooming of follicles, and quality of oocytes.

Data were analyzed using the Graphpad software with a microsoft excel spread sheet. A P-value < 0.05 (Fisher exact test) was taken to be significant. Multinomial regression tests were used as appropriate.

A significant number of follicles were in the 3-6 mm group whereas the population below 35 years constituted the majority. There was no significant difference in basal estradiol and FSH levels among the three groups. Accelerated growth of follicles (zooming) was significantly associated with bigger antral follicles ( P < 0.001) whereas poor quality oocytes were significantly higher in Group 1.

The significant number of poor quality of oocytes produced by such follicles whereas zooming of follicles among the bigger antral follicle group suggest their accelerated development potential and hence the dose of gonadotropin should be adjusted accordingly, indicating evidence of intrinsic abnormality of folliculogenesis in very small follicles.