Using a cell-free RNA (cfRNA) “liquid biopsy” of maternal plasma, researchers at the Carlos Simon Foundation and iPremom enrolled 9,586 pregnant women from 14 hospitals across Spain between September 2021 and June 2024. In a nested case-control analysis of 216 participants, they successfully predicted both early-onset and late-onset preeclampsia well before the onset of symptoms.

By isolating paternal age from female reproductive factors through the exclusive use of donor eggs from young women, the study provides robust evidence that male age plays a critical role in reproductive success, challenging the common assumption that sperm age has little impact once fertilisation occurs.

The findings, presented today at the ESOT Congress 2025, mark a significant step forward in overcoming the biggest challenge in xenotransplantation: rejection by the human immune system.