The present classification systems for perinatal death lack twin‐specific categories, potentially leading to loss of important information regarding the cause of death. This study was done to introduce and test a classification system designed to assign a CoDiT. The research design used was the retrospective cross‐sectional study in the tertiary maternity unit in England.

A multidisciplinary panel designed CoDiT by adapting the most appropriate elements of singleton classification systems. The system was tested by assigning the cause of death in 265 fetal and neonatal deaths from 144 twin pregnancies. The cause of death was validated by another obstetrician blinded to the original classification.

The commonest cause of death irrespective of chorionicity was the placenta; TTTS was the commonest placental cause in monochorionic twins and acute chorioamnionitis in dichorionic twins.

This novel classification system records causes of death in twin pregnancies from postmortem reports with a high inter‐user agreement. We highlight differences in the etiology of death between monochorionic and dichorionic twins.

This study concluded that the new classification system for #twin cause of death ‘CoDiT’ shows high rater agreement.