Pregnancy Outcomes and Postnatal Health from Transferred Mosaic Embryos Following Preimplantation Genetic Testing for Aneuploidy

ABSTRACT Next‐generation sequencing (NGS) has increased the detection of mosaic embryos during preimplantation genetic testing for aneuploidy (PGT‐A). However, evidence regarding the postnatal and childhood health outcomes following mosaic embryo transfer remains limited especially in the Chinese mainland population. This retrospective study analyzed 123 mosaic embryo transfer cycles performed on 112 patients between January 2019 and May 2024. These cycles were matched to 130 euploid embryo transfer cycles based on the preimplantation genetic testing (PGT) indications. Statistical methods including differential analysis and multivariable logistic regression were employed to compare pregnancy outcomes and postnatal health status. Outcomes assessed included pregnancy results, prenatal ultrasound findings, amniocentesis results, neonatal outcomes, maternal complications, pediatric hospitalizations, the length and reasons for hospital stay, and cognitive development at 1 and 3 years of age. Results demonstrated that both clinical pregnancy rates and live birth rates were significantly lower in the mosaic embryo transfer group compared to the euploid group (both p < 0.001), and the miscarriage rate (typically in early pregnancy) rate was higher. Despite these differences, no significant association was observed between mosaic embryo transfer and adverse pregnancy complications, preterm birth, low birth weight, pediatric hospitalization rates, the length or cause of hospitalization, or cognitive development at 1 and 3 years of age. Notably, in ongoing pregnancies resulting from mosaic embryo transfer, persistent mosaicism was observed in 2 cases (4.2%, 2/47). Subgroup analyses revealed no significant differences between segmental mosaic embryos and monosomy/trisomy mosaic embryos in biochemical, clinical, or ongoing pregnancy rates. In contrast, low‐level mosaic embryos demonstrated higher ongoing pregnancy rates ( p = 0.007) and live birth rates ( p = 0.004), alongside lower miscarriage rates ( p = 0.002). These findings indicate that although mosaic embryo transfer may reduce pregnancy and live birth rates, healthy offspring can still be achieved.