Sonographic evaluation of normal and induced ovulation

The adult premenopausal ovary exists in a dynamic state of flux, with ovarian position, size, activity, and structure constantly undergoing changes. Pelvic sonograms must be interpreted with knowledge of the stage of the menstrual cycle and the expected normal range of sonographic findings, because features that are normal in one phase may be abnormal in another. Only against this background knowledge can the challenging task of interpretation of pelvic sonograms be successfully performed. US also plays an increasingly important role in monitoring ovulation induction and alternative methods of fertilization and has improved pregnancy rates by distinguishing between the presence of one or more mature follicles as opposed to a cohort of immature follicles, suggesting the possibility of multiple ovulation with the risks of hyperstimulation or poor pregnancy outcome from multiple gestation, indicating optimum timing of human chorionic gonadotropin administration, allowing detection and confirmation of normal follicular rupture and ovulation, indicating optimum timing of oocyte retrieval in programs of in vitro fertilization with embryo transfer (IVF-ET) or insemination programs, and assessing pathologic pelvic conditions and ovarian accessibility in IVF-ET programs. Oocyte retrieval and embryo transfer are also being performed under US guidance.