Yesterday, Scully expressed some concern that the WTS would use Twin to Twin Transfusion (TTT) syndrome as a “freak of nature that can kill reason” to keep its ban of whole blood transfusions in place.
I explained to Scully that I was actually talking about the natural blood transfers in all monochorionic twin fetuses and not just the monchorionic twin fetuses that develop TTT syndrome.
So why does Twin To Twin (TTT) syndrome happen in only about 12% (Taylor et. al) of monochorionic twin gestation cases? Here is some useful information from Dr. G. Machin Opinion paper (Appendix 3 in the essay):
The connections traverse a special zone of the MC placenta, called the vascular equator, which runs roughly at right angles to a line joining the two cord insertions.
In this section, Dr. Machin explains that the blood systems of each fetus are being connected in a special zone (called the “vascular equator") on the placenta that they share. Later, Machin states this:
Vascular connections cross the equator in three ways: arterio-arterial (A-A), veno-venous (V-V) and arterio-venous (A-V). The anatomy of these connections is explained and illustrated in our recent paper(6). The majority of MC twin placentae have A-V connections, so there is usually intertwin transfusion. The question is: why don’t most MC twins develop TTT? The answer is the everything depends on the combination and direction of connections. Outcomes in MC twin pregnancies are largely determined by the number, type and diameter of vessels running on the placental surface. Whereas transfusion always occurs across A-V connections, other connections (including A-A, V-V and contra-directional A-V) can allow flow back to the donor. When there is under-compensated unidirectional flow in a ‘causative’ A-V, TTT will develop. Each MC placenta has a unique vascular anatomy, and spectrum of severity of TTT depends on the exact anatomy of each MC placenta. Postpartum placental perfusion studies have shown that TTT MC placentae usually have less complicated vascular anatomy, in which a causative A-V connection is compensated for poorly, if at all, by any other connections. MC placentae with numerous connections allow compensation and usually do not develop TTT.
So yes, Scully, there are diseases, like TTT syndrome, that can hurt monochorionic twins fetuses. But, I guess there are other blood diseases that can hurt us. And yes, I think any doctor would tell you that fetuses sharing one placentae is suboptimal. But, Jehovah God’s own answer to protect the fetuses (88 percent of the time) is to provide a complicated vascular structure on the “vascular equator" zone of the placentae with
many artery and vein connections to allow for whole blood to naturally transfer between fetuses. And that usually means TTT syndrome will not develop resulting in healthy identical twin (or more) babies.
Science is interesting and thanks for your comment Scully.
hawk
