Gonadotrophin-releasing hormone (GnRH) agonists and antagonists have been widely used to prevent premature LH surge during ovarian stimulation for in vitro fertilisation (IVF) and embryo transfer (1-3). GnRH agonist suppresses gonadotrophin secretion through both pituitary desensitisation and GnRH receptor down-regulation, whereas GnRH antagonist competes with endogenous GnRH for receptor binding and therefore rapidly inhibits secretion of gonadotrophin (1). It has been suggested that the desensitisation by GnRH agonist has different effects on the intraovarian system than GnRH antagonist (4). Also, GnRH antagonist-treated women showed lower serum and follicular oestradiol concentrations on the day of human chorionic gonadotrophin (HCG) administration during IVF (5-8). This suggests a difference in ovarian oestradiol metabolism between the two protocols.Coasting, i.e., withholding gonadotropin stimulation whilst continuing pituitary desensitisation for a variable number of days is the most popular strategy for the prevention of ovarian hyperstimulation syndrome (OHSS) during ovarian stimulation (9). The above-mentioned differences between agonists and antagonists suggest different effects on serum oestradiol levels during coasting. Therefore, in this retrospective analysis, we aimed to compare the change in serum oestradiol levels after withholding the gonadotropins for coasting between long agonist and antagonist cycles. Material and MethodsAntagonist and long luteal agonist cycles, in which coasting was performed, were analysed in this retrospective analysis. Among 4220 cycles between 2001 and 2006, coasting was performed in 115 cycles. Coasting was performed for the indications of: [1] presence of >20 follicles, which were >10 mm in diameter; and/or [2] presence of high (>4000 pg/mL) serum oestradiol level. In all of these cycles, the follicular diameter for the smallest of the three leading follicles was 15 mm. Serum oestradiol levels were determined daily or every other day during coasting until serum oestradiol levels decreased to <4000 pg/mL. Only women between the ages of 21 and 39 years (n=102) were included in the analysis, to match the groups by age. Antagonist cycles (n=50) were compared with long agonist cycles (n=52) with respect to the duration of coasting and the serum oestradiol levels following withholding of gonadotropins. Pregnancy and implantation rates and the rate and severity of OHSS were also compared. The severity of OHSS was determined according to the Golan criteria (10). Cycle characteristics were compared by using the Student's t-test and chi-square test, where appropriate. Continu- ABSTRACTBackground: GnRH agonists and antagonists have different mechanism of action, and therefore serum estradiol levels might differ during coasting in IVF.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.