Monochorionic diamniotic pregnancy

Case contributed by Dr Alexandra Stanislavsky


16 weeks pregnant. Suspected monochorionic monoamniotic pregnancy on earlier scan.

Patient Data

Age: 25 years
Gender: Female

Selected images of the placenta, umbilical cord insertions and membranes in an MCDA pregnancy. Note the typical appearance of the intertwin membrane with "T-sign" at the margin. There is a single anterior placenta. Twin 1 (maternal left) cord insertion is centric, twin 2 (maternal right) has a velamentous cord insertion. 

Images of fetal morphology are not provided, however were normal and growth concordant.

Case Discussion

Representative images demonstrating the appearance of the intertwin membrane in a monochorionic diamniotic (MCDA) twin pregnancy. 

Note single placental mass, with centric insertion of twin 1 umbilical cord and velamentous insertion of twin 2 cord. Velamentous cord insertion may be associated with intrauterine growth restriction; in this case however the pregnancy outcome is unknown.

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