[Monitoring of the preovulatory follicles--a comparison of ultrasound and laparoscopy].

Accurate prediction of the time of ovulation is important for infertile women considering in vitro fertilization. Preovulatory follicular growth was measured by using ultrasound every 2 to 24 hours and laparoscopic aspiration of the follicular fluid was performed in sixty six patients with clomiphene-HCG cycle. The mature oocyte was examined in aspirated fluid. In ten fertile women with spontaneous cycles, preovulatory follicles were measured by ultrasound and the largest follicular diameter was 18.7 +/- 1.9mm (mean +/- S.D.), of which the growth rate was 1.39mm/day. Follicular diameter was well correlated with the aspirated volume (r = 0.847; p less than 0.001), the largest diameter of the dominant follicle being 28.3 +/- 1.5mm and the second follicle 23.3 +/- 6.1mm. The second follicle grew rapidly after HCG injection and the mature oocyte was collected in spite of rupture of the dominant follicle. The size of the dominant follicle reaching a maximum diameter of 25mm remained almost unchanged for 24 hours before ovulation. The recovery rate of mature oocyte by ultrasound in monitoring of follicles was 87.5%. Ultrasound is a useful technique to use in monitoring follicular growth and ovulation.