Does the timing of cabergoline administration impact the rate of mild/moderate ovarian hyperstimulation syndrome in women with a GnRH agonist trigger? MethodsWe conducted a retrospective cohort analysis of 285 IVF patients at risk of OHSS who received a GnRH agonist trigger from 2011 to 2019 at McGill University Health Centre. Group 1 (Trig, n=101) began taking cabergoline 0.5 mg orally for 7 days at the time of GnRH agonist trigger, while Group 2 (Retriev, n=184) started taking cabergoline on the day of oocyte retrieval. The rates of OHSS were then compared between the groups using analysis of variance and chi-square analysis, where appropriate. ResultsThe baseline demographic characteristics of the two groups were similar. Trig appeared to be at a slightly higher risk of OHSS based on a significantly higher antral follicle count (20.2±4.2 vs. 19.0±4.3; P=0.02), higher number of stimulated follicles >10 mm at trigger (25.7±7.0 vs. 22.8±8.3, P=0.003), and higher peak serum E2 level (17,325±2,542 vs. 14,822±3,098; P=0.0001). The Trig group had lower rates of mild and moderate OHSS (24% vs. 36%; P=0.045). Neither group had any patients who developed severe OHSS. Trig had fewer patients presenting with pelvic free fluid (13% vs. 23%; P=0.03), lower hematocrit (37.8±4.8% vs. 40.5±4.2%; P=0.0001), higher albumin concentrations (30.4±2.7 vs. 29.5±2.0; P=0.01), and lower potassium concentrations (3.9±0.5 vs. 4.2±0.7; P=0.0002). ConclusionCabergoline at the time of trigger as compared to the time of collection should be investigated to assess its role in reducing the rates of mild/moderate OHSS.