TTTS Australia Inc. - NSW TTTS Treatment Group

Twin Twin Transfusion Syndrome (TTTS) is a serious complication of an identical twin pregnancy in which there is only one placenta (afterbirth). TTTS occurs in 10-15% of identical twin pregnancies.

When TTTS occurs, there is an unequal sharing of blood between two fetuses due to blood vessels that communicate between the two fetuses in the single placenta. In the most serious cases, one fetus (called the Recipient twin) is larger and surrounded by an excessive amount of amniotic fluid, while the other fetus (known as the Donor twin) is smaller and appears to be stuck against the uterine wall due to the reduced amount of amniotic fluid.

In the early stages of the disease, signs include a large amount of fluid around in the larger, Recipient twin and a smaller amount of fluid around the smaller, Donor twin. The bladder of the Donor twin may still be seen during an ultrasound examination.

As the disease progresses, the Donor (smaller twin) may no longer have a visible bladder and a very small amount of amniotic fluid or no amniotic fluid. This is referred to as “stuck twin” syndrome, because the smaller twin actually appears to be stuck to the uterine wall or wrapped up in the amniotic membrane ("vacuum packed").

Ultrasound Doppler studies provide information about the condition of the blood circulation for both of the twins. As the condition worsens, the Donor twin does not receive enough blood and the Recipient receives too much blood. In the advanced stages, an excessive amount of fluid builds up within the Recipient twin due to heart failure. This is called “hydrops”. Related symptoms include swelling of the skin around the head, swelling of the abdomen (ascites), poor contractions of the heart, and heart failure. Either twin can develop hydrops, but more often it occurs in the recipient twin. The pregnancy may be lost from heart overload in the larger twin, lack of enough blood getting to the smaller twin, or preterm (early) labour because of the excess fluid causing the uterus to be 'overstretched'.

The purpose of this education booklet is to provide information to you about TTTS, the treatment options, the NSW TTTS Treatment Group, and to answer questions you may have.

The process of having twins occurs in many ways. Twins may be either “fraternal” or “identical”. In fraternal twins, each fetus has his or her own placenta and amniotic sac (bag of waters). In identical twins, the two fetuses may share the same amniotic sac, placenta or both.
TTTS only occurs in identical twins.
Most identical twins share blood vessels through the placenta, but twins with TTTS have unequal sharing of blood. One twin may not get enough blood while the other becomes overloaded with too much blood. This can lead to heart failure or growth problems.

If not treated, severe Twin Twin Transfusion Syndrome has a mortality rate close to 100%.
Current treatment methods include:

In serial amniocentesis excess fluid is removed from the amniotic sac of the Recipient (larger) twin with a needle. Repeated removal of fluid may be needed. Each time fluid is removed, 1-4 litres may be obtained. How often fluid is withdrawn depends upon how severe the case. It may need to be done as often as every second day.

Pregnancies that develop signs of TTTS after 26 weeks gestation are usually managed by Serial Amniocentesis as the fetuses are at a viable age (able to live outside the womb). The success rate (at least one survivor) for this technique varies, but may be as high as 60-70 %.

The advantage of Serial Amniocentesis is that it may prevent pre-term 1abour and thereby extend the pregnancy for a few more weeks. Also there are trained doctors at many centers throughout the country who may perform this procedure.

The main disadvantages of this approach are that it does not fix the basic problem (unequal sharing of blood), therefore making repeat removal of fluid necessary, each with its own risk of trauma, infection, or pregnancy loss. If one baby dies from the disease, the shared blood flow between the babies may allow for the second twin to bleed into the dead twin. This may cause death (up to 40%) or brain or neurological damage (15 - 25%). Serial amniocentesis may also cause the membranes to detach from the uterine wall. This may make any other form of invasive intrauterine therapy more difficult. Furthermore the success rate with this method is poor when the disease is severe (Stages III & IV - see below for staging of the severity of the disease).

In severe cases of TTTS, one of the fetuses may be extremely sick at the time of presentation. Attempts to save both fetuses in this case may be futile, as the sicker fetus may die despite all efforts. Spontaneous death of the unhealthy fetus may in turn cause death or neurological damage to the co-twin. An umbilical cord ligation may be performed to save the co-twin from harm.

The chance of miscarriage following this procedure is about 10%. Umbilical cord ligation is offered only in severe cases and the intent is to save the life of the other twin.

Laser surgery may be performed to stop the sharing of blood between the two fetuses.

The object of this method is to treat TTTS by laser coagulating the specific vessels that cause the problem of blood sharing in this syndrome and spare the remainder of the vessels. The laser is used to seal the vessels to stop the blood flow between the fetuses.

Overseas centres report an 84% survival rate for at least one baby and 50 percent for both, with an incidence of neurological complications of 2 to 5%. The surgery is done under general anaethesia which limits the fetuses from moving and interfering with the delicate procedure. A small incision (1cm) is made in the mother’s belly to insert an endoscope and laser fibre, under combined ultrasound and endoscopic guidance.

The endoscope is a long, narrow telescope with a light and camera on the end. The blood vessels are identified and sealed through the endoscope. For patients who have an anterior placenta (located in front of the uterus), we use endoscopes that curve upwards.

The main advantage to this method is that the disease is corrected in the majority of cases with a single treatment even for the more severe stages of the disease (Stage III & IV). In addition, cerebral palsy and other complications caused by the death of one of the twins are less likely to occur ( approximately 5% ) than with serial amniocentesis. If one fetus dies, the other twin is not likely to be affected.

The purpose of surgery is to separate the circulation between the babies by using the laser to seal the vessels connecting the two. In essence, these babies are now like fraternal twins. They are no longer sharing blood and each has its own portion of the placenta. The question many couples raise is why, in some cases, only one baby survives? This depends on how much placenta each baby receives when the placenta forms. At the time of surgery, we can’t give more placenta to either baby, nor can we tell how much placenta each baby has. According to research on placentas inspected after birth, each baby needs approximately 30% of the placenta to survive. If there is a loss of one of the fetuses after surgery, the other baby will be less likely to be affected since they are no longer sharing blood vessels.

Loss can occur anytime from the time of surgery. If both babies are doing well after one month, both are likely to survive.

Needling of the dividing membrane (fetal septostomy): This procedure consists of purposely disrupting the dividing membrane between the fetuses with a needle. This results in equalization of the fluid volumes between the sacs. There is little data to support this therapy.

Moreover, the disruption of the membrane may lead to death of the fetuses from cord entanglement. For these reasons we are generally not in favour of this procedure.

After reviewing all information and options, you may decide you do not want to continue this pregnancy.

Patients are considered for surgery when the pregnancy is between 16 and 26 weeks gestation. Further criteria include the following:

There is a low incidence of these complications as precautions are taken to minimise these risks. You will be placed on antibiotics to prevent infection. Very small instrumentation is used to help prevent bleeding and preterm labour. All patients are evaluated thoroughly prior to surgery .

TTTS is staged in an effort to offer the most appropriate treatment for the level of disease present. Surgery may not be indicated in all cases.

In Stage I there is a small amount of fluid (known as oligohydramnios) in the donor and a large amount of fluid (polyhydramnios) in the recipient. At this stage, surgery may not be indicated but close observation for a change in condition is recommended.

In Stage II, along with poly / oligohydramnios, there is no visible bladder in the donor. At this stage, laser surgery is considered.

Stage III is characterized by Critically Abnormal Dopplers (CADs), which means one of the babies has abnormal blood flow. Laser Surgery is offered for this stage. If laser surgery is not possible, umbilical cord ligation may be performed if absolutely necessary.

In Stage IV, all of the above findings are present and the baby is hydropic. This means there is swelling of the head and abdomen (ascites), the heart contracts poorly, and heart failure is present. The natural history of this disease has shown that at this stage a baby is not likely to survive.

Stage	Poly/Oligo Hydramnios	Absent Bladder in Donor	Critically Abnormal Dopplers	Hydrops	Demise
I	Yes	No	No	No	No
II	Yes	Yes	No	No	No
III	Yes	Yes	Yes	No	No
IV	Yes	Yes	Yes	Yes	No
V	Yes	Yes	Yes	Yes	Yes

Before surgery, you will not be allowed to eat or drink for a defined amount of time (usually 6-8 hours). This is to prevent the risk of vomiting during surgery. For a morning procedure you will be asked to fast from midnight the night before.

When it is time to be admitted to the hospital for surgery, check in at the admissions desk at Westmead Hospital at the time arranged by Leanne Luck, Midwife consultant in High Risk Pregnancy. You will be taken to the antenatal ward B6C and oriented to the ward.

An ultrasound will be done prior to going to the operating room to confirm the babies’ heartbeats. When you arrive in the operating room you will be moved to the operating table. You will be covered with a warm blanket to keep you comfortable during surgery. You will be given medication through your intravenous (IV) tubing to put you to sleep. General anesthesia will be provided. Surgery is performed under general anesthesia because it is important that the babies do not move during surgery.
After you are asleep, a catheter will be put in your bladder to drain urine and will remain in place for about four hours after surgery.
During surgery, one or two small incisions, approximately 2 cm long, are made on the abdomen. The incisions are so small that they only require band-aids to cover after surgery.
In most cases surgery lasts one to two hours, but this can vary depending on a number of factors.

Following surgery, you will be taken to the Recovery Room until fully awake. This usually takes about one hour. After you are fully awake, you will be taken back to the antenatal ward (B6C).

Medication will be given after surgery to relax the uterus and stop any contractions. Pain or discomfort after surgery seldom occurs. If present, it is usually very minimal. If needed, pain relief medication will be offered. The catheter will be removed from your bladder about four hours after surgery. Your husband or other support person may remain with you in your room.
You will be given liquids to drink during the evening after surgery. Following this you may have regular food as tolerated. Activity is restricted to toilet privileges only, but this depends upon your specific condition.
The day after surgery, a follow-up ultrasound will usually be done. The reason for this is to allow time to see changes in fluid volume and blood flow in each baby.
You will remain in the hospital one to two days.

After surgery, your original doctor will resume your care for the rest of the pregnancy and delivery. You and your doctor/midwife should feel free to contact us with any questions or concerns.
Weekly ultrasounds are recommended for the next month. After that time, if all is going well, ultrasounds are performed every two weeks or as directed by your doctor.
Although you are returning home, we continue to follow your pregnancy closely. Please make arrangements with your doctor to forward all of your ultrasounds and any other information or test results to us. We also will ask your doctor to send the placenta to our pathologist after birth. As this is a new treatment we are carefully monitoring the outcomes of patients and babies, so we will also try to follow up all surviving babies.

Representatives from Social Work and Pastoral Care are available for our patients and families for assistance with psychological, social and spiritual needs. The social woker can assist you with benefits, accomodation, and IPTAAS forms.

If you wish to be referred for laser surgery please have your doctor contact one of the fetal medicine specialists below. This discussion will determine if you might benefit from the procedure. Our program is a collaborative program between most of the specialist hospitals in NSW, but all surgery has been centralised at Westmead Hospital. You may have your initial consultation at Westmead, Liverpool, or Randwick, whichever is most convenient for you.
All ultrasound reports and prenatal records will be requested. Please bring these and your yellow antenatal card to your consultation.

Leanne Luck CNC High Risk Pregnancy
Westmead Hospital
Phone 9845 5555 Page no. 01728

Dr Daniel Challis
Royal Hospital for Women, Randwick
Phone 9382 6098 or 9382 6111
Fax 9382 6706
Dan@challis.com.au