A voluntary reporting system (VRS) is still used to detect adverse events (AEs) in health-care services in many countries. We attempted to apply the Global Trigger Tool (GTT) for the first time in our country and searched for an answer to the question of whether there could be new triggers. Two hundred and forty inpatient records were selected from total of 1,807 inpatient files in the university obstetrics and gynecology clinic between 2018 and 2020. Twenty files per month were reviewed retrospectively using GTT, an approach developed by the American Institute for Health Development. VRS records of the same period were examined. The data were evaluated according to the National Coordinating Council for Medication Error Reporting and Prevention scale and those in the E, F, G, H, I categories were included. The number of AEs per 1,000 patient days was 47.81, AEs per 1,000 patient hospitalizations was 95.83, and hospitalizations with AEs was 9.58%. In the VRS data, 10 of 85 reporting cases were listed in the E category (Damage is temporary and requires intervention), 6 of them were related to fall of the patient, and 4 of them were related to medical device and material safety. By applying GTT, 45 cases in category E and 35 cases in category F (Damage is temporary and requires hospitalization or prolonged hospitalization) AEs were detected in 23 patients (9.58%). The number of AEs reported was 8.3 times higher in the GTT than with VRS. Healthcare related infection, development of complications from any procedure, APTT>100 Seconds, INR>6, Organ Injury - Repair or Removal, All Kinds of Operative Complications were found to be the most sensitive triggers (PPV = 100). There was no difference between the patients with and without AEs in terms of age and number of hospitalization days (p: 0.707, p: 0.618). The sensitivity rate of vaginal dinoprostone use and CRP elevation (30% and 22%, respectively) was higher than the mean sensitivity rate of GTT triggers (15.6%). The GTT is more effective than VRS in detecting AEs. Using vaginal dinoprostone (propess) and high CRP levels could be used as a trigger. The GTT is a credible and fruitful instrument for determining AEs when adapted to the departmental practices.