Mitigating adverse pregnancy and neonatal outcomes through expanded carrier screening in an oocyte donation programme

Overview & Synopsis

Research question: How frequent are adverse outcomes in an oocyte donation programme, and how many recessive conditions can be prevented by implementing expanded carrier screening (ECS)? Design: This retrospective observational study used data from oocyte donation cycles between January 2014 and December 2021 at the Reproductive Medicine Unit of a University Hospital in Spain. Adverse outcomes were studied in 4565 oocyte donation cycles assigned as low-risk at the time of genetic matching. The number of high-risk assignations was identified when ECS was applied to the oocyte donor and recipient's male partner (or sperm donor for double donation). Results: Of 4565 oocyte donation cycles, 67 recipients (1.47%) reported an adverse obstetric or neonatal outcome. A genetic aetiology was confirmed in 25 (37.3%). The remaining 42 (62.7%) cases included congenital malformations, neurodevelopmental disorders and other conditions with unknown genetic origins. Moreover, 211 (4.6%, 211/4565) high-risk assignations were identified where both the oocyte donor and recipient's male partner were carriers of the same autosomal recessive condition. This could have led to an additional 1.15% of children born with an autosomal recessive condition (25% × 4.6%). Additionally, 52 (2.8%, 52/1875) oocyte donor candidates were carriers of X-linked conditions, which would have led to an additional 0.7% (25% × 2.8%) being born with an X-Linked disorder. ECS implementation resulted in a 55.7% reduction in adverse outcome risk, from a potential rate of 3.32% (1.47% + 1.15% + 0.7%) to an actual incidence of 1.47%. Conclusions: ECS reduces the probability that children born from oocyte donation will inherit the recessive conditions screened for. However, certain adverse outcomes remain unavoidable.