The main objective of this study was to evaluate parents’ current demands following the announcement of trisomy 18 and maternal risks.

A single-centre retrospective study was performed in the Paris Saclay Foetal Medicine Department from 2018 to 2021. All patients followed up in the department who had cytogenetic confirmation of trisomy 18 were included.

89 patients were recruited. The most common malformations at ultrasound examination were cardiac or brain abnormalities, distal arthrogryposis as well as severe intrauterine growth retardation. 29% of foetuses with trisomy 18 had more than three malformations. 77.5% of patients requested medical termination of pregnancy. Among the 19 patients who chose to continue their pregnancy, 10 (52.6%) presented with obstetrical complications, of which 7 (41.2%) experienced stillbirth; five babies were born alive with no survival at 6 months.

In France, in the case of foetal trisomy 18, most women request termination of pregnancy. In the post-natal period, the management of a newborn with trisomy 18 is oriented towards palliative care. The mother's risk of obstetrical complications should be part of counselling. Follow-up, support and safety should be the goal of management of these patients, regardless of the patient's choice.