There really isn't anything you can do to prevent acute TTTS or even to know it is happening in some cases. You definitely don't want to delay cord clamping in Baby A because the risk of transfusion is so high. But we were monitoring both babies via doppler and never had any indication that there was acute TTTS until after the birth. Then it was obvious, as one baby was anemic and one was polycythemic.
This was exactly the case with my mono/di twin boys. Born at 40wks, in a hospital, spontaneous labor, med-free vaginal birth (just so you know
). Baby A came out WHITE and lethargic and floppy, Baby B came out like a freight train (7mins later), red in color and screaming. Labor was short < 5 hours total. Baby A was anemic and Baby B was polycythemic.
My understanding is that the change in blood pressure (from contractions) can kick the Acute TTTS in gear. It must take a bit for heart tones to reflect that the donor baby is not getting proper blood supply. Acute TTTS can be very fast and fatal. If you have a long labor, I would assume that eventually donor baby's heart tones would slow way down while recipient baby's heart tones would speed way up (trying to accommodate for extra blood) but at that point - will it be too late? So, this is where the recommendation of c-sec at 36-37 weeks comes into play. If you make it to this point w/out regular TTTS, their theory is that avoiding labor will avoid Acute TTTS (again - labor can kick in the Acute TTTS). They also feel that for every week you are still pregnant after 36 weeks, you have another week where Acute TTTS can come into play (this was the explanation given to me by a HUGE supporter of mono-di c-secs at 36/37 weeks)
At some point I came across a study showing that there is about a 1% chance of Acute TTTS - but I did not save the link (pity). As others have said, there is not a lot of info. out there on Acute TTTS because there is not a lot of research. So, technically, the percentage could be a lot higher because there could be a whole lot of unreported cases out there (mine was not reported). While it disturbs me also to recommend all mono-di twin pregnancies to have a c-sec at 36-37 weeks, I don't think it can be completely dismissed as the OB's having an excuse to section.
Imagine - this is a new area of study. We don't know the actual facts and statistics of how many twins developed and were damaged/dead due to Acute TTTS. Personally, I know that if I didn't bring home two healthy boys due to Acute TTTS, I would have been wishing that I could have done something to change the outcome. FWIW - my boys (2 1/2) are fine too, with no lasting effects from the Acute TTTS - but my perspective has changed a bit now. I'm not sure where I stand on the c-sec recommendation, but I do see where it comes from.
**I also love that the placenta is called the mothercake, and think I will start using that