Foetal loss after chorionic villus sampling and amniocentesis in twin pregnancies: A multicentre retrospective cohort study.

OBJECTIVE: We aimed to determine foetal losses for DCDA and MCDA twins following transabdominal CVS or amniocentesis performed <22+0 weeks. METHODS: Retrospective cohort study conducted in the UK and Belgium 01/01/00-01/06/20. Cases with unknown chorionicity, monochorionic complications or complex procedures were excluded. Uncomplicated DCDA and MCDA twins without invasive procedures were identified as controls. We reported foetal losses <24+0 weeks and losses of genetically and structurally normal foetuses. RESULTS: Outcomes were compared for DCDA foetuses; 258 after CVS with 3406 controls, 406 after amniocentesis with 3390 controls plus MCDA foetuses, 98 after CVS with 1124 controls, and 160 after amniocentesis with 1122 controls. There were more losses