What is twin-twin transfusion syndrome (TTTS)?
Twin-twin transfusion syndrome (TTTS) is a rare condition that happens in about 15 percent of identical twin pregnancies. TTTS can also affect triplets or higher order multiples. twin to twin transfusion syndrome is not related to anything the mother did or did not do during pregnancy.
The majority of identical twins share the same placenta (organ that nourishes the fetus in the womb) and blood flow through the placenta. However, with TTTS, abnormal blood vessel connections form in the placenta and allow blood to flow unevenly between the babies.
It affects each twin differently and both twins are at risk.
- The recipient twin gets too much blood and develops high blood pressure. This twin is overwhelmed with fluid and produces too much urine. The increased urine results in excessive amniotic fluid and overdistension of the uterus, which commonly causes preterm labor. The recipient twin’s heart may also be strained resulting in heart failure and accumulation of fluid within the baby’s body (non-immune hydrops fetalis).
- The donor twin doesn’t get enough blood and becomes dehydrated. This causes the twin not to produce as much urine as it should. Without urine, it doesn’t produce much amniotic fluid and may become “stuck” against the wall of the uterus.
Both fetuses are at high risk for a number of complications including brain damage, complications from preterm birth or death.
How is the condition diagnosed?
It is critical for all multiple gestations to have an ultrasound in the first trimester. This may be the only time we can tell for certain the type of twins (identical or fraternal) and the number of placentas and sacs the babies are in. If the ultrasound shows that your twins are identical and share a placenta, then you’ll be monitored very closely and your doctors will watch for any signs of this condition.
We know that twin to twin transfusion syndrome has developed when the amount of fluid in the bag of waters for the babies is dramatically different. TTTS occurs when the amount of fluid in the recipient baby’s bag is high (polyhydramnios), and the amount of fluid in the donor baby’s bag is low (oligohydramnios). We also look at the amount of urine in the babies’ bladders and the pattern of blood flow in some of the babies’ blood vessels to determine the severity of TTTS.
How is twin-twin transfusion syndrome treated?
Without treatment, this condition can be deadly for both twins. We know that this diagnosis can be very scary, but a decision often needs to be made quickly to help increase the odds of survival for the twins.
Our team will help you decide what option works best for your situation. Your doctor might recommend the following treatments:
- Laser treatment. A thin tube is placed into the uterus and into the amniotic sac. Your doctors will be able to examine the placenta and abnormal blood flow. The laser treatments will close off blood vessels that are problematic. With a laser treatment, odds increase for a premature delivery. If that’s the case, the babies will be cared for in the newborn intensive care unit (NICU). The survival rate for at least one baby after laser treatment is between 65 and 75 percent.
- Amnioreduction. The goal here is to remove extra amniotic fluid from the “recipient” twin with a needle. This will help you feel more comfortable, too. This procedure is done during pregnancy and is low-risk. Because it doesn’t treat the cause TTTS, excess amniotic fluid might come back. If that’s the case, the treatment will need to be performed again.
- Selective reduction. This would be the last option for treatment. During this minimally invasive surgery, your doctor will stop the blood flow to the dying twin to help the surviving twin stay alive. This treatment is only used when the condition is very advanced and the at-risk twin could die immediately.
After any of these procedures, you and your babies will be monitored very closely. After a few days, you will be able to leave the hospital, but will need to come back for ultrasounds after the procedure to see if the condition is coming back or if any complications are found.
How will twin-twin transfusion syndrome affect my baby during and after surgery?
The goal for treatment is to get both babies to an age where they can live outside of the womb. If you go into labor when you are at or are close to full term, you may be able to deliver with your own OB doctor at the hospital of your choice. Often times this is not possible, and one of the unique services that we offer at the Fetal to Newborn Care Center is complete obstetrical care for our high-risk twins with TTTS. In collaboration with your referring OB doctor we can arrange to have all of your testing at Miami Valley Hospital and one of our maternal-fetal medicine specialists perform your delivery. We will work with you to develop the best delivery plan for you and your babies. Your options for delivery might change over time as you get closer to your due date.
After delivery, the babies will need to be cared for in the NICU if they are born prematurely. For the most part, the degree of prematurity determines how much care the babies will need.
The most common question we get is: Which baby is more at risk? Unfortunately, both are at an equal amount of risk for different reasons (either too much blood flow or not enough blood flow). Our goal is to do whatever we can to give both babies the best outcome possible.