Here is a list
Death around birth
Separation of siamese twins
The twins body leaves from the womb during pregnancy
Total miscarriage of one twin
Abortion causing total miscarriage of one twin
The twin's body remains in the womb
A vanishing twin pregnancy - in utero death and disappearance of one twin in the first trimester (fetal resorption)
Abortion leading to death one twin in the womb
The twins body remains within the body of the survivor
Fetus in fetu
The death of a twin in the Dream of the Womb leaves a very specific memory and that memory includes details of how the twin died. Until that memory is clear, healing is blocked or delayed in definitely. But in the back of your mind the idea will grow and grow as the picture puzzle that is your Dream of the Womb falls into place. The idea of twins will get stronger in your mind every day.
One womb twin survivor told me:
You would not believe the number of times that 'twins' are coming into my life right now, randomly, and repeatedly in conversations with other people.