Clinical course and perinatal management of fetuses and newborns affected by trisomy 13 and 18: a retrospective single-centre cohort study.

Objectives Trisomy 13 (T13) and 18 (T18) are lethal chromosomal abnormalities. While the prognosis is generally poor, recent evidence suggests that some infants with T13 and T18 are able to survive longer than previously supposed. These findings underline the importance of an individualised approach to perinatal/neonatal care. Methods This retrospective study included 193 pregnancies with T13 and T18 in a single tertiary center between 2005 and 2023. Fetal and maternal characteristics, overall survival, and perinatal and postnatal management were analysed. Results Of 193 affected fetuses, 142 (73.6%) were diagnosed with T18 and 51 (26.4%) with T13. Associated malformations were present in 90.7% (175 cases), with congenital heart defects being the most common (42%). A total of 161 (83,4%) women opted for termination of pregnancy (TOP). Gestational age at diagnosis was significantly higher among women opting to continue pregnancy compared to those opting for TOP. Among women continuing pregnancy, 65.6% (21/32) experienced intrauterine fetal death. Eleven pregnancies resulted in live births. Survival times for infants born alive ranged from 6 min to 60 days, with a median survival time of 18 h. Newborns affected by T18 lived significantly longer than those with T13 (median 33 h vs 6.5 h).Conclusion: The duration of survival in infants with T13 and T18 remains highly variable and difficult to predict. Management strategies must therefore be clarified within an interdisciplinary framework, supporting families through informed, individualised decision-making while balancing the poor prognosis with a focus on comfort, dignity, and quality of life.