Comparison of foetal and neonatal mortality of monochorionic monoamniotic and monochorionic biamniotic twin pregnancies

Objectives. - To compare the mortality of monochorionic-monoamniotic (MCMA) and monochorionicbiamniotic (MCBA) twin pregnancies, from 14 weeks of gestation to 28th day of life, before and after exclusion of major congenital malformations.Methods. - We conducted a retrospective cohort study in two level 3 maternity units of the Hospices civils de Lyon (France) including all patients with a monochorionic twin pregnancy between January 2013 and December 2020. We excluded TRAP sequences and conjoined twins.Results. - A total of 38 MCMA and 658 MCBA pregnancies were included. We showed an increase in overall mortality in the MCMA group compared to the MCBA group (31.6% versus 16.4%, P = 0.03) even after exclusion of major congenital malformations (20.3% versus 9.5%, P = 0.01). The main cause of mortality found in the MCMA group was the occurrence of unexpected IUGR.Conclusions. - MCMA pregnancies have a higher foetal and neonatal mortality rate than MCBA pregnancies even after exclusion of congenital malformations related to the occurrence of unexpected MFIU.& COPY; 2022 Elsevier Masson SAS. All rights reserved.