Pregnancy outcomes in egg donation programs are similar when vitrified imported oocytes are compared to egg-sharing in a retrospective cohort study.

Background : In the past decade, the use of donated oocytes has increased, with egg donation (ED) cycles accounting for nearly 10% of all assisted reproductive technology (ART) in the United States, with live birth rates exceeding 50% per cycle. Legal frameworks for ED vary across countries; for example, Brazil permits voluntary and shared donation but prohibits commercial donation, leading to imported egg-sharing programs. Despite the growing use of both fresh and vitrified oocytes, no studies have yet compared pregnancy rates between these different egg-sharing programs. Does the use of imported vitrified oocytes from an international bank result in similar pregnancy rates when compared to an egg-sharing donation with fresh oocytes? Methods : This study is a retrospective cohort including in vitro fertilization (IVF) cycles involving egg donation from January 2010 to December 2023. Patients were divided into two groups: those participating in the egg-sharing program and those receiving imported vitrified oocytes from an international bank. Results : A total of 391 patients were included, with 224 from egg-sharing group (comprising 251 IVF cycles) and 170 from the imported vitrified oocyte group (comprising 179 IVF cycles). The data between the groups were as follows, respectively: mature oocytes: 6.11±3.03, vs 6.88 ±1.69, p = 0.001; total embryos formed: 3.10±1.78, vs 3.26±1.73, p = 0.373, clinical pregnancy rate: 40.1%, vs 47.4%, p = 0.099, live birth and ongoing pregnancy rate: 30.7% vs 38%, p = 0.084, birth weight 2842±765 vs 3048± 547, p = 0.040, small for gestational age 21.6 vs 7.7%, p = 0.036. In the imported oocytes group, the pregnancy rates according to endometrial thickness were as follows: <8mm: 23.5%, 8-12mm: 53.8%,>12 mm 34.6%, p = 0.002. Conclusions : Egg recipient treatment using imported vitrified oocytes demonstrated similar laboratory outcomes and clinical pregnancy rates compared to the egg-sharing program. Additionally, recipients using vitrified oocytes achieved higher pregnancy rates when transfers were conducted with an endometrial thickness of 8-12 mm.