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Twin-to-Twin Transfusion Syndrome Workup

  • Author: Terence Zach, MD; Chief Editor: Ronald M Ramus, MD  more...
Updated: Dec 30, 2015

Laboratory Studies

After delivery, the newborn work-up should include the following laboratory studies:

  • CBC count: The donor twin is frequently anemic at birth, whereas the recipient twin is frequently polycythemic at birth.
  • Calcium: Hypocalcemia is frequently present in the donor twin.
  • Glucose: Hypoglycemia may be present in either twin.
  • Creatinine: Either twin may have evidence of renal dysfunction.
  • Platelet count: Thrombocytopenia can occur in either twin.
  • Bilirubin: Hyperbilirubinemia may develop in the polycythemic recipient twin.

Imaging Studies

Sonographic findings of TTTS during pregnancy include the following:

  • Significant discrepancy in size of same-sex fetuses
  • Monochorionic placentation
  • Significant disparity in the amount of amniotic fluid between the fetuses with the smaller twin having oligohydramnios
  • Smaller fetus with an absent stomach and bladder
  • These pregnancies are at risk for preterm delivery. This may be related to the uterine overdistention from the twin gestation and polyhydramnios. Cervical shortening is also more common so transvaginal assessment of the cervix should also be done. [4]

Neonatal imaging should include the following:

  • Neonatal brain ultrasonography: Because ischemia of the brain can occur during fetal development in either the donor or recipient twin, brain ultrasonography should be considered in both twins born with TTTS. Twins born prematurely are susceptible to intraventricular hemorrhage and periventricular leukomalacia.
  • Neonatal echocardiography: Myocardial dysfunction, myocardial hypertrophy, valvular insufficiency, and pericardial effusions can be detected in either twin.
  • Neonatal renal ultrasonography: Abnormal renal echogenicity may be present in either twin and indicates hypoxic-ischemic cortical necrosis.
  • Neonatal abdominal ultrasonography: Ascites may be present if hydrops fetalis occurs.
  • Neonatal chest radiography: Pleural effusions and cardiomegaly may be present if hydrops fetalis occurs.

Other Tests

The risk for aneuploidy in monochorionic twin gestations is not increased compared with a singleton gestation of the same age. Invasive procedures to salvage the pregnancy would not be recommended if lethal aneuploidy (ie, T13 or T18) is seen, so evaluation of the amniotic fluid should be offered to assess for aneuploidy.[5]



Amnioreduction can be done immediately once the diagnosis of TTTS is made. This can be performed by placing a 20- or 18-gauge spinal needle into the amniotic cavity of the fetus with polyhydramnios under ultrasonographic guidance and connecting this to 1 L evacuated containers. Several liters of fluid can be removed by this method.

The patient should then be followed weekly to evaluate for evidence of improvement, ie, monitoring the amniotic fluid volume of both fetuses. If there was some improvement in the amniotic fluid of the donor, then repeat amnioreductions can be performed if and when the polyhydramnios recurs around the recipient.

Serial ultrasonography to assess fetal growth are also recommended and these can be done every 2-4 weeks. Once an advanced gestation is obtained nonstress testing can be performed to assess fetal well-being.

If there is any evidence of cardiac failure, ie, cardiac hypertrophy or hydrops, in either fetus or if there is no response to the amnioreduction, then the patient should be referred to a center that can perform fetoscopic laser photocoagulation of the placenta.

A systematic review and meta-analysis by Rossi et al found that a small number of cases with laser therapy are affected with neurologic impairment (cerebral palsy being the most frequent) , signs of which begin in infancy. All infants, even those who appear to be healthy, should be closely followed.[6]



The most useful staging system for TTTS was developed by Quintero:[7]

Table. TTTS Staging System (Open Table in a new window)

Stage Oligohydramnios/


Absent Urine in Donor Bladder Abnormal Doppler Blood Flows Hydrops Fetalis Fetal Demise
I + - - - -
II + + - - -
III + + + - -
IV + + + + -
V + + + + +
Contributor Information and Disclosures

Terence Zach, MD Department Chair, Professor, Department of Pediatrics, Section of Newborn Medicine, Creighton University School of Medicine

Terence Zach, MD is a member of the following medical societies: American Academy of Pediatrics

Disclosure: Nothing to disclose.


Michael J Barsoom, MD, FACOG Director, Division of Maternal-Fetal Medicine, Alegent Health at Bergan Mercy Medical Center

Michael J Barsoom, MD, FACOG is a member of the following medical societies: American College of Obstetricians and Gynecologists, American Institute of Ultrasound in Medicine, Society for Maternal-Fetal Medicine

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Chief Editor

Ronald M Ramus, MD Professor of Obstetrics and Gynecology, Director, Division of Maternal-Fetal Medicine, Virginia Commonwealth University School of Medicine

Ronald M Ramus, MD is a member of the following medical societies: American College of Obstetricians and Gynecologists, American Institute of Ultrasound in Medicine, Medical Society of Virginia, Society for Maternal-Fetal Medicine

Disclosure: Nothing to disclose.

Additional Contributors

Robert K Zurawin, MD Associate Professor, Chief, Section of Minimally Invasive Gynecologic Surgery, Department of Obstetrics and Gynecology, Baylor College of Medicine

Robert K Zurawin, MD is a member of the following medical societies: American College of Obstetricians and Gynecologists, American Society for Reproductive Medicine, Association of Professors of Gynecology and Obstetrics, Central Association of Obstetricians and Gynecologists, Society of Laparoendoscopic Surgeons, Texas Medical Association, AAGL, Harris County Medical Society, North American Society for Pediatric and Adolescent Gynecology

Disclosure: Received consulting fee from Ethicon for consulting; Received consulting fee from Bayer for consulting; Received consulting fee from Hologic for consulting.

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Monozygotic twins with monochorionic, diamniotic placentation.
Monozygotic twins with monochorionic, monoamniotic placentation.
Table. TTTS Staging System
Stage Oligohydramnios/


Absent Urine in Donor Bladder Abnormal Doppler Blood Flows Hydrops Fetalis Fetal Demise
I + - - - -
II + + - - -
III + + + - -
IV + + + + -
V + + + + +
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