Site Map

Twin-to-twin transfusion syndrome

TTTS; Fetal transfusion syndrome

Twin-to-twin transfusion syndrome is a rare condition that occurs only in identical twins while they are in the womb.

Animation

Causes

Twin-to-twin transfusion syndrome (TTTS) occurs when the blood supply of one twin moves to the other through the shared placenta. The twin that loses the blood is called the donor twin. The twin that receives the blood is called the recipient twin.

Both infants may have problems, depending on how much blood is passed from one to the other. The donor twin may have too little blood, and the other may have too much blood.

Symptoms

Most of the time, the donor twin is smaller than the other twin at birth. The infant often has anemia, is dehydrated, and looks pale.

The recipient twin is born larger, with redness to the skin, too much blood, and a higher blood pressure. The twin that gets too much blood may develop cardiac failure because of the high blood volume. The infant may also need medicine to strengthen heart function.

The unequal size of identical twins is referred to as discordant twins.

Exams and Tests

This condition is most often diagnosed by ultrasound during pregnancy.

After birth, the infants will receive the following tests:

• Blood clotting studies, including prothrombin time (PT) and partial thromboplastin time (PTT)
• Comprehensive metabolic panel to determine electrolyte balance
• Complete blood count
• Chest x-ray

Treatment

Treatment may require repeated amniocentesis during pregnancy. Fetal laser surgery may be done to stop the flow of blood from one twin to the other during pregnancy.

After birth, treatment depends on the infant's symptoms. The donor twin may need a blood transfusion to treat anemia.

The recipient twin may need to have the volume of body fluid reduced. This may involve an exchange transfusion.

The recipient twin may also need to take medicine to prevent heart failure.

Outlook (Prognosis)

If the twin-to-twin transfusion is mild, both babies often recover fully. Severe cases may result in the death of a twin.

References

Malone FD, D'Alton ME. Multiple gestation: clinical characteristics and management. In: Lockwood CJ, Copel JA, Dugoff L, et al, eds. Creasy and Resnik's Maternal-Fetal Medicine: Principles and Practice. 9th ed. Philadelphia, PA: Elsevier; 2023:chap 37.

Obican SG, Odibo AO. Invasive fetal therapy. In: Lockwood CJ, Copel JA, Dugoff L, et al, eds. Creasy and Resnik's Maternal-Fetal Medicine: Principles and Practice. 9th ed. Philadelphia, PA: Elsevier; 2023:chap 34.

Unal ER, Newman RB. Multiple gestations. In: Landon MB, Galan HL, Jauniaux ERM, et al, eds. Gabbe's Obstetrics: Normal and Problem Pregnancies. 8th ed. Philadelphia, PA: Elsevier; 2021:chap 39.

BACK TO TOP

Review Date: 7/12/2023  

Reviewed By: John D. Jacobson, MD, Professor Emeritus, Department of Obstetrics and Gynecology, Loma Linda University School of Medicine, Loma Linda, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

Health Content Provider 06/01/2025

A.D.A.M., Inc. is accredited by URAC, for Health Content Provider (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics. This site complied with the HONcode standard for trustworthy health information from 1995 to 2022, after which HON (Health On the Net, a not-for-profit organization that promoted transparent and reliable health information online) was discontinued.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- 2024 A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.