The study aims to evaluate the risk factors and incidence of thromboembolic events among adult women with cancer who underwent controlled ovarian hyperstimulation (COH) for fertility preservation.

Retrospective, descriptive cohort analysis of patient demographics, medical history, cancer type/treatment, laboratory values, thrombosis within 6 months of COH.

4 of 127 study participants experienced a venous thromboembolic event within 6 months of COH. The median time between oocyte aspiration and the event was 0.25 years (range = 0.10–0.50). The average age at time of event was 25.3 years (SD = 5.3). Three of four thrombotic patients had ovarian cancer, one had breast cancer. All had received surgery and chemotherapy for treatment. All underwent an antagonist cycle ovarian stimulation protocol — none developed ovarian hyperstimulation syndrome. The average anti-mullerian hormone level at the time of hyperstimulation in the thrombosis group was 1.6 (SD = 1.3), compared to 3.6 in the non-thrombosis group. The average max estradiol level reached during ovarian stimulation was 1281.3 (SD = 665.3) in the thrombosis group and 1839.1 (SD = 1513.9) in the non-thrombosis group. Thromboembolic events were not directly associated with mortality.

Within this small descriptive study, the incidence of thromboembolic events in women with cancer undergoing COH for fertility preservation is high. Cancer may play a greater role than COH in thrombosis risk. Ovarian cancer patients who undergo ovarian stimulation may have an increased risk compared to other cancer types. These findings may inform future, prospective studies to determine the role of thromboprophylaxis.