[Ultrasound monitoring of follicle growth in IVF]

Vaginal sonography is a well-established method to monitor follicular growth and to detect the optimum time for induction of ovulation with hCG. In this study we found significantly less and smaller follicles in the left ovary compared to the right. However, during the procedure of oocyte retrieval we found an equal number of follicles and oocytes in both ovaries. We assume therefore that the used sonographic method is less valid for the left ovary compared to the right. The reason could be that on the left side the ovary is often hidden behind the sigma which makes visualization by ultrasound more difficult. Vaginal sonography should therefore be performed on a gynecological chair where it is easier to bring the probe closer to the left ovary. On the basis of follicular fluid volume measurements at the puncture the sizes of the follicles on day hCG were calculated and resulted in a range of 14.7-20.7 mm for the average of all follicles.