Twin to Twin Transfusion Syndrome (TTTS)

Twin to twin transfusion syndrome (TTTS) is a serious disorder that occurs in identical twins and higher-order multiples who share a placenta. This occurs when the blood vessels of the babies’ shared placenta are connected. This results in one baby (this twin is referred to as the recipient) receiving more blood flow, while the other baby (this twin is referred to as the donor) receives too little. Twin to twin transfusion syndrome is also referred to as chronic inter-twin transfusion syndrome. TTTS occurs about 15 % of the time among identical twins. Fraternal twins are not at risk for this syndrome because they do not share a placenta.

What can I do to make sure my twins do not develop Twin to Twin Transfusion Syndrome?

TTTS is a random event that cannot be prevented by doing or not doing anything specific. It is not a hereditary condition.

How is Twin to Twin Transfusion Syndrome diagnosed?

Your healthcare provider may suspect this disorder if any of the following is seen during an ultrasound:

  • A marked difference in the size of fetuses of the same gender
  • The difference in size between the two amniotic sacs
  • The difference in the size of the umbilical cords
  • A single placenta
  • Evidence of fluid build up in the skin of either fetus
  • Findings of congestive heart failure in the recipient twin
  • Polyhydramnios (excess amniotic fluid) in the recipient twin
  • Oligohydramnios (decreased or too little amniotic fluid) in the donor twin

A mother whose twins have TTTS may experience:

  • A sensation of the rapid growth of the womb
  • A uterus that measures large for dates
  • Abdominal pain, tightness, or contractions
  • A sudden increase in body weight
  • Swelling in the hands and legs in early pregnancy

What treatment options are available for Twin to Twin Transfusion Syndrome?

Up until recently, twin to twin transfusion syndrome has claimed the lives of both babies, but technology has brought about two new treatment options for this condition.
The use of amniocentesis to drain off excess fluid appears to improve the blood flow in the placenta and reduce the risk of preterm labor.
Amniocentesis can save approximately 60% of affected babies. Laser surgery can also be used to seal off the connection between the blood vessels and appears to save 60% of affected babies.
Delivery is also an option if your healthcare provider determines the twins’ lungs have reached maturity.

What are the advantages of having laser surgery instead of an amniocentesis?

Amniocentesis may need to be done repeatedly throughout the pregnancy to maintain proper blood flow in the placenta, while laser surgery usually only requires one treatment.

What are the potential complications?

  • Premature labor either due to ruptured membranes or induction
  • Respiratory, digestive, heart, or brain defects in the recipient twin because of excess fluids
  • Donor twin developing anemia
  • Fetal demise/death

Is there anything else that I need to about this diagnosis?

The Twin to Twin Transfusion Syndrome Foundation recommends that weekly ultrasounds be performed after 16 weeks through the end of the pregnancy to monitor TTTS. They recommend that this be done even if the warning signs of TTTS have decreased.
The TTTS Foundation can be contacted at or at 1-800-815-9211.

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