What Is Twin-Twin Transfusion Syndrome?
Twin-twin transfusion syndrome (TTTS) is a rare, serious condition that can occur in pregnancies. This happens when identical twins share a placenta (monochorionic). Abnormal blood vessel connections form in the placenta. They allow blood to flow unevenly between the fetuses. One twin − called the donor – becomes dehydrated. The other twin − called the recipient − develops high blood pressure. The recipient produces too much urine and over fills the amniotic sac.
TTTS is a disease of the placenta. It affects each twin differently. The donor twin does not produce as much urine as it should. This causes a low amount of amniotic fluid and poor fetal growth. The recipient twin has more urine than usual. This leads to an enlarged bladder and too much amniotic fluid. The extra fluid in the recipient fetus can put a strain on the heart. This can lead to heart failure. There is no known cause of TTTS.
Without treatment, this condition can be fatal for one or both twins. Fetal surgery is sometimes needed to treat the condition. The prognosis is better when TTTS develops after 20 weeks’ gestation.
Getting a diagnosis of twin-twin transfusion syndrome is an emotional experience. Sometimes decisions about treatment must be made quickly. At the Cincinnati Children’s Fetal Care Center, we are here to help.
Evaluation & Diagnosis of TTTS
The Cincinnati Children's Fetal Care Center evaluates, gives a diagnosis, and recommendations for treatment in a one- or two-day visit. Surgery may take place within a day of the diagnosis.
When patients come to our center for an evaluation, the first step is to check for the presence of TTTS. We use ultrasound, fetal MRI, and fetal echocardiography (a detailed examination of both babies’ hearts by ultrasound) to give more information about the severity of the condition, which helps us recommend a treatment plan if TTTS is confirmed.
Staging Twin-Twin Transfusion Syndrome
Our team uses the Quintero staging system to figure out the severity of TTTS on a scale of one to five. Five being the most serious.
Stage I: One baby has too much fluid and the other baby does not have enough fluid.
Stage II: Cannot see the bladder fill in the donor fetus on ultrasound.
Stage III: Abnormal blood flow through the umbilical cord or fetal vessels around the heart for one or both babies.
Stage IV: An abnormal fluid collection in more than one body cavity, also known as hydrops. This can happen in one or both twins.>/p>
Stage V: The death of one or both babies.
Using the results of the fetal echocardiography, we also put the severity of the recipient fetus’ heart condition as mild, moderate or severe.
After the test results are available, the patient meets with members of the team. This team includes a maternal-fetal medicine specialist, a surgeon, and a nurse coordinator. We spend as much time with the patient and family in this meeting as needed. The goal is to explain the test results and create a treatment plan.
TTTS Treatment Options
The treatment plan we recommend depends on the severity of the condition and how far along the pregnancy is. Referring doctors can participate in this meeting, in person or by phone. We give them information about all parts of our evaluation, treatment and follow-up recommendations.
Expectant Management (Monitoring the Pregnancy)
In less severe cases, surgery may not be needed. If that is the case, we will use ultrasound and fetal echocardiography to monitor the fetuses during the pregnancy. If their condition worsens, our team will work with the patient, the patient’s family and referring doctor to decide what treatment is best. Sometimes, early delivery is the best option.
Amnioreduction (Draining Excess Amniotic Fluid)
When the fetuses are only mildly affected by TTTS, we may recommend amnioreduction to drain the excess amniotic fluid from the recipient twin’s sac. If amnioreduction does not work, patients may be given the option to move forward with selective fetoscopic laser photocoagulation (SFLP), known as laser surgery.
Selective Fetoscopic Laser Photocoagulation (Laser Surgery)
When the pregnancy is more severely affected by TTTS, the team may recommend selective fetoscopic laser photocoagulation, or laser surgery. This procedure involves making a small incision in the mother’s abdomen and inserting a trocar, or small metal tube, into the uterus. The surgeon then passes a fetoscope (a kind of medical telescope) through the metal tube to see all the blood vessel connections on the surface of the placenta shared by the twins.
After all the abnormal blood vessel connections are found, the laser is used to treat these vessels. The laser disconnects them permanently. Afterward, the surgeon drains the extra amniotic fluid around the recipient fetus through the trocar. The surgery is then complete.
The location of the placenta will help decide the type of anesthesia used for the laser surgery. If the placenta is “posterior,” or located on the back wall of the uterus, we recommend intravenous (IV) sedation and a local anesthetic. However, if the placenta is “anterior,” or located on the front wall of the uterus, we recommend IV sedation, a local anesthetic, and possibly an epidural.
After laser surgery, most patients stay in the hospital for one day. Post-operative ultrasound and fetal echocardiography are then repeated five days after the laser surgery to reassess the fetal condition. We will work with the patients’ maternal-fetal medicine specialist and obstetrician to make sure they have followed up care at home.
Long-Term Prognosis for TTTS
Twin-twin transfusion syndrome often causes premature birth. In this case, babies need care in a neonatal intensive care unit.
Most babies who are successfully treated for twin-twin transfusion syndrome live normal, healthy lives. However, some experience mild complications, such as anemia. This can be easily treated. More serious problems include brain injury and heart failure. If local specialists are not available, specialists at Cincinnati Children’s can help by providing long-term, expert care for these children.
Experience & Expertise
Our experienced maternal and fetal care specialists offer a complete range of diagnostic tests and treatment options. The team at the Cincinnati Children’s Fetal Care Center has completed more than 1,984* evaluations for TTTS since 2004. Our center is among only a handful of centers that can offer surgical interventions for triplet pregnancies affected by this condition. We also treat patients who have an anterior placenta. An anterior placenta is positioned toward the front of the mother’s womb. This location increases the technical difficulty of surgery.
*Data based on patients cared for by the Cincinnati Children's Fetal Care Center from Feb. 1, 2004, through June 30, 2020.
- Our team has experience with the most challenging surgical cases. This includes those with hydrops (Stage IV TTTS) and those involving an anterior placenta. Half of patients who have undergone SFLP at the center have an anterior placenta.
- Our team is experienced in treating triplet pregnancies affected by TTTS. We have outcomes similar to those with twin pregnancies.
- We offer consultations for patients at any gestational age. We complete SFLP as early as 16 weeks’ gestation and up to 27 weeks’ gestation.
- We offer different options for anesthesia during SFLP. We recommend the least invasive option whenever possible.
- Our center has a very low rate of surgical complications.
- We offer novel therapies. For example, our center was among the first to give mothers medication to treat the recipient twin’s cardiomyopathy before fetal surgery. Cardiomyopathy is a disease of the heart muscle. This drug therapy can improve recipient twins’ survival rates.
- We take part in international Stage I TTTS clinical trials. This allows us to better understand this disease, improve treatment strategies, and predict long-term outcomes.
TTTS Surgery Volumes & Outcomes
The Fetal Care Center has performed:
- More than 1,984 evaluations for TTTS, including evaluations for 92 sets of triplets
- More than 1,290 fetal surgical interventions for TTTS, including more than 1,197 selective fetoscopic laser photocoagulation (SFLP) procedures
One measure of success for SFLP is the percentage of babies who survive the procedure and are delivered safely. *
|Quintero Stages I , II , III
|Survival of at Least One Twin
|Survival of Both Twins
|Quintero Stage IV
|Survival of at Least One Twin
|Survival of Both Twins
* Data reflects twin gestations from July 1, 2011 through June 30, 2020 with available outcome data.