This is a monocentric retrospective observational study. The study investigates the impact of the operator performing the oocyte retrieval on the cumulative live birth rate (CLBR).

The objectives of the study are as follows:

• To evaluate whether the operator performing the oocyte retrieval influences the probability of pregnancy, expressed as the cumulative live birth rate (CLBR).
• To assess whether operator performance improves with increased experience.

To address the study objectives, data will be collected using a specific internal web-based database. All oocyte retrieval procedures performed at the Humanitas Fertility Center from January 2013 to December 2022 will be included in the evaluation. Outcomes will be expressed in terms of CLBR.

Inclusion Criteria:

The study database will include patients who underwent oocyte retrieval procedures with the intention of achieving pregnancy at the Humanitas Fertility Center between January 2013 and December 2022, including repeated ART cycles.

Operator experience will be assessed based on the number of previously performed oocyte retrieval procedures. All operators who performed at least 50 procedures, either at IRCCS - Humanitas Research Hospital or at another institution, will be included in the study.

Exclusion Criteria:

Patients who underwent preimplantation genetic testing (PGT) cycles, as well as those who underwent cryopreservation for oncological or elective purposes, will be excluded from the study.

Operators who performed fewer than 50 oocyte retrievals, either at IRCCS - Humanitas Research Hospital or at another institution, will be excluded. Additionally, the first 50 procedures performed by each operator will not be included in the dataset.

The study sample will include all operators who performed oocyte retrievals for ART cycles at the Humanitas Fertility Center between January 2013 and December 2022, in accordance with the inclusion and exclusion criteria outlined above.