Although transvaginal ultrasound-guided oocyte retrievals (OR) are performed routinely worldwide, there is very little systematic data about its complications. METHODS: We performed a prospective cohort study following the perioperative and post-operative complications of over 1058 ORs. Additionally, we assessed the pain experienced during the OR. RESULTS: A total of 1166 OR were performed during the study period, of which 1058 (90.7%) ORs were included prospectively. Incomplete data meant that the remaining 9.3% were excluded. No complications were caused by sedation or general anaesthesia. Vaginal bleeding was observed in 2.8% of procedures, without any cases of intra-abdominal bleeding. An injury of pelvic structures (a ureteral lesion) occurred in one case. No case of pelvic infection, but one case of unexplained fever, was observed. A severe ovarian hyperstimulation syndrome (OHSS) occurred in 2.7% of cases. Although most patients tolerated the OR well, 3% of patients experienced severe to very severe pain after the OR and 2% of patients were still suffering from severe pain 2 days after the procedure. The pain level increased with the number of oocytes retrieved. About 0.7% of patients required hospitalization for pain treatment. CONCLUSIONS: Patients can be reassured that overall OR is a safe procedure. However, patients have to be counselled about the minor risks of the OR. The literature on complications is reviewed in the article.