Letrozole and gonadotropins versus luteal estradiol and GnRH-antagonist protocol: additional concerns

Abstract

In their recent comparative study on letrozole and gonadotropins versus a luteal estradiol and gonadotropin-releasing hormone (GnRH) antagonist protocol, Elassar et al. (1Elassar A, Engmann L, Nulsen J, Benadiva C. Letrozole and gonadotropins versus luteal estradiol and gonadotropin-releasing hormone antagonist protocol in women with a prior low response to ovarian stimulation. Fertil Steril. Published online April 22, 2011.Google Scholar) concluded that “aromatase inhibitor regimens can be a feasible alternative to the LPG protocol in recurrent low ovarian response.” Based on that study, the efficacy of both protocols seems similar. However, there are some differences, both in the agents and in the total dose of gonadotropins administered and the estradiol levels. The concern of interest is the comparative cost effectiveness. Although it might be expected that the protocol with the lower required total dose of gonadotropins would be more effective, a further comparative systematic assessment on the costs and utility of both protocols is required before a final conclusion. Reply of the AuthorsFertility and SterilityVol. 95Issue 8PreviewWe thank Dr. Chen and Dr. Wiwanitkit for their interest in our article (1). Dr. Chen’s comments in his letter are highly valid, and we agree that oral ovarian stimulation medications (including both clomiphene citrate and aromatase inhibitors) are associated with increased levels of luteinizing hormone (LH) that may contribute to premature luteinization. This theory was addressed in prior studies cited in our article (2, 3) where elevated LH levels were found in normally responding patients. Thus, the article he referred to (4) that reported the increase in LH pulse amplitude after letrozole administration was not the first. Full-Text PDF Discussion on letrozole-Gn-antagonist group needing an early start of antagonistFertility and SterilityVol. 95Issue 8PreviewI read with great interest the article by Elassar et al. (1) in which they addressed the risk of a premature luteinizing hormone (LH) surge (LH ≥10 mIU/mL occurring before the detection of the leading follicle ≥18 mm in diameter) in the letrozole and gonadotropin-releasing hormone (GnRH) antagonist group and suggested that “an early start and possibly a higher dose of the antagonist should be considered when using letrozole.” This is a good concept, but they did not explore the cause. They mentioned “ovaries with diminished ovarian reserve are more prone to a premature LH surge.” However, it is not the cause leading to the high rate of premature LH surge associated with letrozole supplementation. Full-Text PDF Letrozole and gonadotropins versus luteal estradiol and gonadotropin-releasing hormone antagonist protocol in women with a prior low response to ovarian stimulationFertility and SterilityVol. 95Issue 7PreviewTo compare in vitro fertilization outcomes after ovarian stimulation using letrozole/antagonist (LA) versus luteal-phase estradiol (E2)/gonadotropin-releasing hormone (GnRH) antagonist (LPG) in poor responders. Full-Text PDF