Bangalore: Did you know that there are different varieties of twins? Imagine two individuals living in two different rooms and eating from two different plates. Now imagine these two individuals eating from the same plate. Does it sound different?
Twin babies in the mothers womb face a similar scenario. They could be in two different sacs (Diamniotic) and can have one or two source of nutrition (placenta/chorion). This is called Dichorionic Diamniotic - DCDA (two babies, two sacs, two placentae) or Monochorionic Diamniotic- MCDA (2 babies, 2 sacs, 1 placenta). There are also rarer situations where 2 babies, 1 sac, 1 placenta (Monochorionic, Monoamniotic-MCMA) may exist. Conjoined twins (Siamese twins) are MCMA where twins are attached to each other.
Twin to Twin Transfusion Syndrome (TTTS ) is a well known complication of MCDA twin pregnancy. The problem is when there are communicating vessels on the common placenta in MCDA twins.
This leads to blood being preferentially transfused from one twin (donor) to another twin (recipient), therefore causing overload on recipient twin and growth restriction of the donor twin . Most of such twin pregnancies can develop complications which may even cause death of the co- twin.