A. Incorrect. There is no inter-twin membrane.
B. Incorrect. There is no inter-twin membrane. Although it may be difficult to see a membrane in MCDA pregnancy later in pregnancy, you should be able to see one in the first trimester.
C. Correct. There is a twin pregnancy with no inter-twin membrane.
D. Incorrect. There are clearly two embryos.
Fig 1 Reproduced with permission from Dr A Kurtz, Thomas Jefferson University Hospital, Philadelphia |