Today is World TTTS (Twin to Twin Transfusion Syndrome) Awareness day, and December is TTTS Awareness month. If you've been reading my blog for a while, you may recall that our twins, Cuddlebug and Bearhug, are TTTSsurvivors. From what I have read, diagnosis and treatment has improved considerably since I was pregnant with our twins 8 years ago. Still, awareness is crucial to helping women who are pregnant with multiples get the information they need and for their doctors to be on the lookout for possible signs of TTTS. It is a life-threatening condition so the earlier it can be detected and treatment options evaluated, the better.
What is Twin to Twin Transfusion Syndrome?
TTTS is a disease of the placenta that affects identical twins who share a placenta. It occurs when the shared placenta contains abnormal blood vessels connecting the two babies, and results in one baby (the "recipient") receiving too much blood / nutrients, while the other baby (the "donor") receives too little. Cuddlebug was our "donor" twin and Bearhug was our "recipient," which is why Bearhug was red and bigger at birth, with his heart struggling to pump because his blood was thick like syrup. Cuddlebug was pale, smaller, and anemic, with his body struggling to make its own red blood cells to make up for the shortage. Our boys were not diagnosed with TTTS until delivery, which thankfully was early because I had developed pre-eclampsia. Despite the complications of prematurity, their early delivery saved their lives, because it's unlikely they could have survived much longer in the womb.
A little primer on twinning
In order to better understand how TTTS happens, it helps to understand how twins develop. Fraternal (dizygotic) twins occur when two eggs are fertilized by two sperm. Fraternal twins have two sacs and two placentas.
Identical (monozygotic) twins occur when a single egg is fertilized by a single sperm, and then during early cell division, the embryo splits an extra time to create two genetically identical embryos. If the split occurs before day 4, the twins will have separate sacs and placentas, just like fraternal twins. If the split occurs between days 4 - 8, the twins will share an outer sac and a placenta, but will have separate inner sacs (monochorionic/diamniotic). That was the case with our boys. If the split occurs between days 8 - 12, they will share both an inner and outer sac (monochorionic/monoamniotic) and a placenta. A split occurring after day 12 generally results in conjoined twins.
I heard it explained once as the later the split, the more "connected" the twins will be, and essentially babies are at risk for TTTS when they are "connected" at the placenta.
If you are pregnant
TTTS can happen to anyone. It is essential to have an ultrasound within the first 3 months of pregnancy to determine whether you are carrying multiples and if so, whether they share a placenta and inner/outer sac. That way, extra monitoring can be started early if you are carrying multiples who are at risk for TTTS.
If you are carrying multiples who are at risk, it's important to know that there is hope! Even with a shared placenta, there may not necessarily be uneven distribution of blood and nutrients. Monitoring is critical to help catch any potential problems as early as possible. If signs begin to appear that there may be a problem, there are treatment options available that have been successful for many babies.