Twin-To-Twin Transfusion Syndrome

In TTTS, the recipient twin's blood can become thick and difficult to pump around the body. This may lead to heart failure, generalized soft tissue swelling, and in some cases, fetal death. The donor twin is at risk for failure of the kidneys and other organs because of inadequate blood flow.

Because of the blood vessels that connect the circulations of the two fetuses across the shared placenta, if one twin dies, the other twin faces significant risk of death or damage to vital organs. If one twin dies, the surviving twin has up to a 40 percent risk of some form of brain injury. Unfortunately, without treatment, about 70 to 80 percent of twins with TTTS will die. Survivors may have injuries to their brains, hearts or kidneys.

With fetoscopic laser intervention, a treatment performed during pregnancy, the outcome is more hopeful. At UCSF's Fetal Treatment Center — one of the first centers in the world to use fetoscopic laser intervention for TTTS — survival rates for at least one twin are greater than 85 percent, and for both twins are approximately 60 percent.

Maternal Mirror Syndrome

In cases of extreme fetal tissue swelling, called hydrops, the pregnant woman may be at risk for maternal mirror syndrome. In maternal mirror syndrome, the mother's condition mimics that of the sick fetus. The mother may develop symptoms similar to pre-eclampsia, such as vomiting, hypertension, body swelling that's greater than usual, excessive protein in the urine and dangerous build-up of fluid in the lungs, called pulmonary edema.

While this is rare, it is imperative that the pregnant woman be carefully followed. Care for TTTS must include continued, optimal obstetric care for the mother with surveillance for such maternal conditions, in addition to managing the complicated twin pregnancy.

Reviewed by health care specialists at UCSF Benioff Children's Hospital.

Related Information

UCSF Clinics & Centers

Fetal Treatment Center
1855 Fourth St., Second Floor, Room A-2432
San Francisco, CA 94158
Phone: (800) 793-3887
Fax: (415) 502-0660
Appointment information

Intensive Care Nursery
1975 Fourth St., Third Floor
San Francisco, CA 94158
Phone: (415) 353-1565
Fax: (415) 353-1202

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