ABSTRACT
The ovary has two essential physiologic responsibilities: The periodic release of oocytes and the production of the steroid hormones, estradiol, and progesterone.
Both activities are integrated into the continuous repetitive process of follicle growth and maturation, ovulation, and corpus luteum formation and regression, which constitute the so-called ovarian cycle. The ovarian cycle is under pituitary gonadotropic control: Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are synthesized and secreted by the pituitary, and together they play a central part in regulating the menstrual cycle and ovulation. Therefore, a basic knowledge of gonadotropic control of ovarian function is an essential requirement for a proper understanding of ovulation-induction techniques using exogenously administered gonadotropins. Thus, this chapter begins with a review of the role of FSH and LH in the control of follicular growth and function. This is followed by a section addressing the development of pituitary gonadotropins, from urinary products to recombinant medications, and stressing the advantages of using the biotech drugs. The three gonadotropins involved in ovulation induction [FSH, LH, and human chorionic gonadotropin (hCG)] are now commercially available and produced in vitro by recombinant DNA technology (rhFSH, rhLH, rhCG). These highly specifi c monohormonal products have permitted important advances in our understanding of gonadotropin action at the cellular level, and also provide us with the perspective of preparing consistent-formulation regimens for ovulation induction or tailoring therapy with FSH and LH, individually or combined, according to the individual patient’s needs (1-3). On the above evidence, the third section in this chapter is devoted to contemporary strategies for ovulation induction in the anovulatory patient. The object of ovulation induction is to restore the ovulatory state and restore fertility potential but producing ideally only one ovulatory follicle. Both the most appropriate gonadotropin to use and pros and cons of different regimens of gonadotropin administration are discussed separately for World Health Organization (WHO) group II and WHO group I anovulation. The chapter
concludes by providing the reader with current therapeutic modalities for inducing multiple follicular developments (the so-called controlled ovarian hyperstimulation) in the already ovulating patient undergoing treatment with assisted reproductive techniques (ART). These different goals require different approaches to how the ovaries are stimulated.
