Twin to Twin Transfusion Syndrome

Evergreen's Fetal Therapy program provides diagnosis and treatment of complicated fetal problems that require surgery while the baby is still in the womb.

Evergreen Hospital is one of only a handful of centers in the United States currently able to provide both surgical and nonsurgical treatments for Twin-to-Twin Transfusion Syndrome (TTTS):

• Fetoscopic laser photocoagulation (surgical treatment)
• Serial Amnioreductions (nonsurgical treatment)

Patient Stories

"We couldn't sit around and do nothing."

It was maternal-fetal medicine specialist Dr. Martin Walker and a pioneering program at Evergreen Hospital involving cutting-edge in-utero surgery that saved the girls’ lives when Dennis was 18 weeks pregnant.

Patient: Karen Dennis, with Anna and Katie

What is Twin to Twin Transfusion Syndrome?

TTTS is a condition that occurs in identical twins who share a common placenta (monochorionic twins).

Connections between the twins on the surface of the placenta are common, and are usually in balance, with blood flowing in both directions equally.

On occasion, the connections are unbalanced, and one baby is chronically losing or donating blood to his or her sibling. The baby losing the blood is called the "donor" and the one receiving the blood is called the "recipient".

Left untreated, the donor over time receives insufficient nutrition from the placenta, leaving it smaller and dehydrated.

On the other hand, the "recipient" receives too much nutrition and blood from the placenta and his or her amniotic sac becomes full with excessive amounts of amniotic fluid. Eventually, the recipient twin can develop heart failure when he or she can no longer cope with the extra blood volume.

Without treatment, neither twin survives in 80 to 90% of the cases. The outcome is dramatically improved with treatment.

How Common is It?

Twins occur naturally in 1 in 84 pregnancies. About one third of twins are identical and two thirds of them share the same placenta.

10-20% of these twins end up with some degree of unequal sharing of blood.

How is TTTS Diagnosed?

TTTS is usually diagnosed by ultrasound early in the pregnancy.

As the condition advances, the bladder of the donor twin becomes too small to see, and the blood flow in the umbilical cord and heart of the babies becomes abnormal.

In advanced cases, the recipient appears swollen and one or both of the twins may spontaneously die.

What Treatments are Available?

There are a number of treatment options for TTTS:

• Fetoscopic laser photocoagulation is an in-utero surgical procedures that seals the connections between the babies and brings their blood and nutrition volumes back into balance.
• Serial amnioreduction (frequent amniocentesis) can be used to attempt to equalize the pressure in each baby's amniotic sac, and helps to reduce the risks of preterm labor.
• Due to the potential for poor outcomes, and with no other safe therapeutic options available, some families may opt to terminate the entire pregnancy, if TTTS is diagnosed early.

If you would like to arrange a consultation, please call:

Melissa Dorn, RN, MN
425.899.3537
mldorn@evergreenhealthcare.org