The effect of ovarian stimulation on endothelial function—a prospective cohort study using peripheral artery tonometry

Abstract

Context: Gonadotropin-releasing hormone agonist (GnRH-a) serves as an alternative to human chorionic gonadotropin (hCG) to trigger final oocyte maturation, while it significantly reduces the risk of ovarian hyperstimulation syndrome (OHSS), probably by attenuating vascular/endothelial activation. Objectives: The objectives of this work are to compare the effect of different modes of final follicular maturation (hCG vs GnRH-a) following ovarian stimulation (OS) for in vitro fertilization (IVF) on endothelial function. Design and Setting: A prospective cohort study was conducted at a tertiary medical center. Participants: Patients age 37 years or younger, undergoing OS for IVF, were allocated into 2 groups according to the type of final follicle maturation: the hCG group (n = 7) or the GnRH-a group (n = 8). Intervention: Endothelial function was assessed by measurement of the peripheral arterial tonometry in reaction to temporary ischemia at 3 study points: day 3 of menstrual cycle (day 0), day of hCG/GnRH-a administration (day trigger) and day of oocyte pick-up (day OPU).The ratio of arterial tonometry readings before and after ischemia is called the reactive hyperemia index (RHI). Decreased RHI (< 1.67) indicates endothelial dysfunction. Main Outcome Measures: The main outcomes measures of this study included endothelial function at 3 study points during OS with different modes of triggering final follicular maturation. Results: The mean RHI values at day 0 were within the normal range for all patients and comparable between both groups (hCG: 1.7 ± 0.3 vs GnRH-a: 1.79 ± 0.4, P = .6). All patients presented a decrease in RHI values on day trigger, which did not differ between the 2 groups (1.62 ± 0.3 vs 1.4 ± 0.2, respectively, P = .2). However, the hCG group demonstrated a further decrease in RHI on day OPU, whereas patients who received GnRH-a had restored normal endothelial function reflected by increased RHI values (1.4 ± 0.2 vs 1.75 ± 0.2, respectively, P = .03). Conclusions: Triggering final follicular maturation with GnRH-a restored normal endothelial function, whereas hCG trigger resulted in a decrease in endothelial function.