Purpose <p>The purpose of this study is to assess whether discontinuing routine serum hormone testing following gonadotropin-releasing hormone (GnRH) agonist trigger affects the incidence of empty follicle syndrome (EFS) and embryological outcomes in controlled ovarian stimulation (COS) cycles.</p> Methods <p>This retrospective cohort study analyzed 3834 COS cycles at a single fertility center from May 2020 to May 2024. Cycles were grouped based on post-trigger testing: 1964 with routine serum hormone measurement and 1870 without. The primary outcome was EFS, defined as failure to retrieve oocytes despite adequate follicular development. Secondary outcomes included the number of oocytes retrieved, mature oocytes, fertilization rates, and utilizable embryos.</p> Results <p>The incidence of EFS did not significantly differ between groups (0.87% with testing vs. 1.07% without; <i>p</i> = 0.06). In GnRH agonist-triggered cycles, the incidence was 0.74% with testing and 0.96% without (<i>p</i> = 0.53). After adjusting for age, trigger medication type, and estradiol level, there was no significant difference in the odds of EFS (adjusted OR 1.26; 95% CI, 0.63 to 2.53; <i>p</i> = 0.52). Secondary outcomes showed statistically significant improvements in the group without testing: oocytes retrieved (mean 12.6 vs. 12.0; <i>p</i> = 0.03), mature oocytes (mean 7.3 vs. 6.4; <i>p</i> &lt; 0.01), and embryos suitable for clinical use (mean 4.0 vs. 3.6; <i>p</i> &lt; 0.01). Fertilization rates were similar between groups.</p> Conclusion <p>The discontinuation of routine hormone testing following the GnRH agonist trigger did not increase the incidence of EFS and was associated with comparable embryological outcomes. These findings suggest that routine testing may be unnecessary in most cases, supporting a selective approach, potentially reducing clinical burden and cost without compromising patient care.</p>