Gonadotropin-Releasing Hormone Antagonist in in Vitro Fertilization Superovulation

Abstract

The use of gonadotropin-releasing hormone (GnRH) antagonists in in vitro fertilization superovulation remains controversial. The GnRH agonist 'long protocol' has been seen as the gold standard for many years. Comparisons and meta-analyses of the efficacy of GnRH antagonists and agonists have been largely inconclusive, with the dataset being contaminated with outdated reports of poorer efficacy with GnRH antagonists, which have stemmed from studies of their use as a second-line drug in older women and women who were poor responders. This work cannot reflect the actual clinical effectiveness of GnRH antagonist and must be interpreted with care. The major advantages of GnRH antagonists use in superovulation include a gentler and more patient-friendly stimulation cycle with less hypoestrogenic side effects, with the potential to lower the risk of ovarian hyperstimulation and enhanced embryo growth. Our current clinical experience with GnRH antagonists in in vitro fertilization is limited, although there are a growing number of in vitro fertilization centers embracing this new technology. There is a clear need for a modern, suitably powered clinical trial to demonstrate the place of GnRH antagonist-based superovulation protocols and in subgroups of patients, such as polycystic ovary syndrome or poor responders.

Random Start or Emergency IVF/in vitro Maturation: A New Rapid Approach to Fertility Preservation

“…A number of variations to this basic design have been used. These include: treatment with GnRH agonists beginning in the mid-luteal phase of the cycle preceding FSH ovarian stimulation, downregulation of endogenous pituitary gonadotropin secretion which results in an improved response and prevents premature ovulation [23]; use of GnRH antagonists concurrently with FSH stimulation to inhibit premature ovulation [24]; and use of estradiol antagonists (e.g., clomiphene citrate) or aromatase inhibitors (e.g., letrozole) to amplify endogenous gonadotropin secretion by reducing estradiol negative feedback on gonadotropin secretion [25]. All three of these variations in stimulation protocol involve starting FSH, clomiphene or letrozole during the early-mid follicular phase.…”