Number and size of antral follicles as predictive factors in vitro fertilization and embryo transfer.
OBJECTIVE
The purpose of the study was to evaluate whether number and size of antral follicles can predict the outcome of in vitro fertilization-embryo transfer.


METHODS
A total of 113 patients were prospectively included into this study. After 19 days of down-regulation, number and size of follicles were determined by using recent three-dimensional transvaginal ultrasound technology. Before application of gonadotropin, all follicles had been defined as antral follicles. According to size, antral follicles were categorized into four different groups: group I included antral follicles < 5 mm, group II follicles 5-10 mm; group III 11-20 mm; and group IV > 20 mm. Pregnant and non-pregnant patients were compared in terms of their number of antral follicles of group I-IV. These four groups were then compared regarding implantation rate, number of retrieved oocytes, endometrium thickness, and age.


RESULTS
Pregnant patients showed an significant higher number of follicles with the size between 5 and 10 mm (P = 0.04). A significant correlation was found between number of retrieved oocytes and antral follicle size of 5-10 mm (P = 0.0001). Antral follicles with a diameter between 5 and 10 mm decreased significantly with age (P = 0.008). In group III and IV, a significant correlation was found between antral follicle size (P = 0.016) and serum estradiol level after gonadotropin-releasing hormone-agonist down-regulation (P = 0.011).


CONCLUSIONS
We demonstrated that patients with a higher number of follicles between 5 and 10 mm showed a significantly higher pregnancy rate, whereas patients with a dominant number of antral follicles > 11 mm have a higher cancellation rate due to ovarian low response.
Pöhl
M
M
Institut for Assisted Reproduction, Vienna, Austria.
Hohlagschwandtner
M
M
Obruca
A
A
Poschalko
G
G
Weigert
M
M
Feichtinger
W
W
D004624:Embryo Transfer; D004958:Estradiol / Q000097:blood; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D006080:Ovarian Follicle / Q000000981:diagnostic imaging* / Q000378:metabolism; D011237:Predictive Value of Tests; D011247:Pregnancy; D011446:Prospective Studies; D014463:Ultrasonography / Q000379:methods
D004958:Estradiol