Pain after oocyte retrieval in women with endometriosis undergoing fertility preservation or in vitro fertilization

Research question Do women with endometriosis undergoing oocyte retrieval for fertility preservation (FP) experience the same level of pain as those undergoing oocyte retrieval for in vitro fertilization (IVF)? Design This was a retrospective cohort study including 796 women with endometriosis undergoing oocyte retrieval for FP and IVF between January 2020 and October 2022. In total, 401 women underwent oocyte retrieval for FP and 395 for IVF. Postoperative pain assessments were compared between the two groups using a numeric rating scale (NRS). Results The FP group was younger (32.1±4.2 years vs 35.1±4.1 years, p<0.001), with a lower BMI (22.8±3.9 kg/m2 vs 24.6±4.4 kg/m2, p<0.001) and lower AMH levels (1.8±1.5 ng/mL vs 2.15±2.11 ng/mL, p=0.026). The estrogen levels on the day of ovulation trigger were higher in the FP group (2188±1152 pg/mL vs 2081±995 pg/mL, p=0.004). The prevalence of adenomyosis and digestive endometrial lesions was lower in the FP group, (14% vs 29%, p<0.001 and 16% vs 25%, p=0.003, respectively). After oocyte puncture, more patients in the FP group had an NRS score >3 (moderate to severe pain) than in the IVF group (20% versus 14%, p=0.018). PPOS protocol was identified as an independent predictive factor of greater postoperative pain (OR 2.30, 95% CI 1.06-5.15, p=0.039). Conclusion Women with endometriosis undergoing FP reported more intense postoperative pain in the recovery room than those undergoing IVF. The PPOS protocol of ovarian stimulation could be responsible for more intense pain (NRS score >3) in women with endometriosis, but further studies are necessary to confirm this result.