eMedicine Specialties > Obstetrics and Gynecology > Obstetrical Complications
Twin-to-Twin Transfusion Syndrome
Updated: Jan 29, 2010
Introduction
Background
Twin-to-twin transfusion syndrome (TTTS) is the result of an intrauterine blood transfusion from one twin (donor) to another twin (recipient). TTTS only occurs in monozygotic (identical) twins with a monochorionic placenta. The donor twin is often smaller with a birth weight 20% less than the recipient's birth weight. The donor twin is often anemic and the recipient twin is often plethoric with hemoglobin differences greater than 5 g/dL.
Pathophysiology
TTTS is the result of transfusion of blood from one fetal twin to another twin. The blood transfusion from the donor twin to the recipient twin occurs through placental vascular anastomoses. The most common vascular anastomosis is a deep, artery-to-vein anastomosis through a shared placental cotyledon.
TTTS is a specific complication of monozygotic twins with monochorionic placentation. Monozygotic twins that have a dichorionic placentation are not at risk for TTTS. Monozygotic twins with monochorionic, diamniotic placentation or monochorionic, monoamniotic placentation are at risk for TTTS (see images below).
Monozygotic twins with monochorionic, diamniotic placentation.
Monozygotic twins with monochorionic, monoamniotic placentation.
The clinical features of TTTS are the result of hypoperfusion of the donor twin and hyperperfusion of the recipient twin.
The donor twin becomes hypovolemic and oliguric or anuric. Oligohydramnios develops in the amniotic sac of the donor twin. Profound oligohydramnios can result in the stuck twin phenomenon in which the twin appears in a fixed position against the uterine wall. Ultrasonography typically fails to visualize the fetal bladder because of absent urine.
The recipient twin becomes hypervolemic and polyuric. Polyhydramnios develops in the amniotic sac of the recipient twin.
Either twin can develop hydrops fetalis. The donor twin can become hydropic because of anemia and high-output heart failure. The recipient twin can become hydropic because of hypervolemia. The recipient twin can also develop hypertension, hypertrophic cardiomegaly, disseminated intravascular coagulation, and hyperbilirubinemia after birth.
Frequency
United States
Monozygotic twins occur in 3-5 per 1000 pregnancies. Monozygotic twins can be monochorionic or dichorionic. Approximately 75% of monozygotic twins are monochorionic. Only monochorionic twins are at risk for TTTS. TTTS occurs in 5-38% of monochorionic twins.
Mortality/Morbidity
Severe TTTS has a 60-100% fetal or neonatal mortality rate. Mild-to-moderate TTTS is frequently associated with premature delivery. Fetal demise of one twin is associated with neurologic sequelae in 25% of surviving twins. Fetal blood pressure instability can lead to brain ischemia in either the donor or recipient twin. Ischemia of the fetal brain can result in periventricular leukomalacia, porencephaly, microcephaly and cerebral palsy. The more premature the twins are at birth, the higher the incidence of postnatal morbidity and mortality.
In a review of 135 monochorionic twin pregnancies with single intrauterine death (sIUD), whether spontaneous or procedure related, O'Donoghue et al found that death of the co-twin followed in 22.9% of cases. In the pregnancies that continued after sIUD, the frequency of antenatally acquired brain injury in the co-twin was significantly lower after procedure-related than spontaneous sIUD: 2.6% versus 22.2% (P = 0.003). The investigators conclude that the risk of brain injury is reduced but not negated by procedures that restrict inter-twin transfusion.1
Sex
TTTS only occurs in same sex, monozygotic twins with monochorionic placentation.
Clinical
History
- Women with twin pregnancies who develop twin-to-twin transfusion syndrome (TTTS) frequently complain of a rapidly enlarging abdomen over 2-3 weeks as polyhydramnios develops in the amniotic sac of the recipient twin.
- Other complaints include preterm labor and premature rupture of membranes.
Physical
TTTS should be considered in a pregnant woman carrying monochorionic twins if she develops a rapidly increasing fundal height. After birth, TTTS can be considered if the twins are monozygotic, and significant differences occur in the size or appearance of the twins.
- Donor twin
- Small for gestational age - More than 20% smaller than recipient twin
- Pallor
- Poor peripheral perfusion
- Recipient twin
- Large for gestational age - More than 20% larger than donor twin
- Plethoric and ruddy
- Jaundice
- Hydrops fetalis can be present in either twin in TTTS. These infants have subcutaneous edema, a distended abdomen, and respiratory distress.
Causes
TTTS occurs in monozygotic, monochorionic twin pregnancies when an anastomosis between placental vasculature exists.
More on Twin-to-Twin Transfusion Syndrome |
 Overview: Twin-to-Twin Transfusion Syndrome |
| Differential Diagnoses & Workup: Twin-to-Twin Transfusion Syndrome |
| Treatment & Medication: Twin-to-Twin Transfusion Syndrome |
| Follow-up: Twin-to-Twin Transfusion Syndrome |
| Multimedia: Twin-to-Twin Transfusion Syndrome |
| References |
| Next Page » |
References
[Best Evidence] O'Donoghue K, Rutherford MA, Engineer N, Wimalasundera RC, Cowan FM, Fisk NM. Transfusional fetal complications after single intrauterine death in monochorionic multiple pregnancy are reduced but not prevented by vascular occlusion. BJOG. May 2009;116(6):804-12. [Medline].
Robyr R, Boulvain M, Lewi L, Huber A, Hecher K, Deprest J, et al. Cervical length as a prognostic factor for preterm delivery in twin-to-twin transfusion syndrome treated by fetoscopic laser coagulation of chorionic plate anastomoses. Ultrasound Obstet Gynecol. Jan 2005;25(1):37-41. [Medline].
O'Brien BM. MFM/geneticist view on prenatal management of twins. Am J Med Genet C Semin Med Genet. May 15 2009;151C(2):155-61. [Medline].
Quintero RA, Morales WJ, Allen MH, Bornick PW, Johnson PK, Kruger M. Staging of twin-twin transfusion syndrome. J Perinatol. Dec 1999;19(8 Pt 1):550-5. [Medline].
Cincotta RB, Gray PH, Gardener G, Soong B, Chan FY. Selective fetoscopic laser ablation in 100 consecutive pregnancies with severe twin-twin transfusion syndrome. Aust N Z J Obstet Gynaecol. Feb 2009;49(1):22-7. [Medline].
Chiossi G, Quigley MR, Esaka EJ, Novic K, Celebrezze JU, Golde SH, et al. Nutritional supplementation in monochorionic diamniotic twin pregnancies: impact on twin-twin transfusion syndrome. Am J Perinatol. Nov 2008;25(10):667-72. [Medline].
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Denbow ML, Battin MR, Cowan F, et al. Neonatal cranial ultrasonographic findings in preterm twins complicated bysevere fetofetal transfusion syndrome. Am J Obstet Gynecol. Mar 1998;178(3):479-83. [Medline].
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Elliot JP. Amniocentesis for twin-twin transfusion syndrome. Contemp Ob Gyn. 1992;37:30-47.
[Best Evidence] Fox C, Kilby MD, Khan KS. Contemporary treatments for twin-twin transfusion syndrome. Obstet Gynecol. Jun 2005;105(6):1469-77. [Medline].
Huber A, Diehl W, Bregenzer T, Hackelöer BJ, Hecher K. Stage-related outcome in twin-twin transfusion syndrome treated by fetoscopic laser coagulation. Obstet Gynecol. Aug 2006;108(2):333-7. [Medline].
Machin GA, Keith LG. Can twin-to-twin transfusion syndrome be explained, and how is it treated?. Clin Obstet Gynecol. Mar 1998;41(1):104-13. [Medline].
Milner R, Crombleholme TM. Troubles with twins: fetoscopic therapy. Semin Perinatol. Dec 1999;23(6):474-83. [Medline].
Sueters M, Middeldorp JM, Lopriore E, Oepkes D, Kanhai HH, Vandenbussche FP. Timely diagnosis of twin-to-twin transfusion syndrome in monochorionic twin pregnancies by biweekly sonography combined with patient instruction to report onset of symptoms. Ultrasound Obstet Gynecol. Oct 2006;28(5):659-64. [Medline].
Taylor MJ, Govender L, Jolly M, Wee L, Fisk NM. Validation of the Quintero staging system for twin-twin transfusion syndrome. Obstet Gynecol. Dec 2002;100(6):1257-65. [Medline].
Yamamoto M, Ville Y. Recent findings on laser treatment of twin-to-twin transfusion syndrome. Curr Opin Obstet Gynecol. Apr 2006;18(2):87-92. [Medline].
Further Reading
Keywords
twin-to-twin transfusion syndrome, TTTS, stuck twin syndrome, stuck twin phenomenon, feto-fetal transfusion syndrome, interfetal transfusion syndrome, polyhydramnios, oligohydramnios, hydrops fetalis, thoracocentesis, pericardiocentesis, paracentesis, placental vascular anastomoses, anemia, plethora, polycythemia, hypocalcemia, renal dysfunction, thrombocytopenia, hyperbilirubinemia, intraventricular hemorrhage, periventricular leukomalacia, myocardial dysfunction, myocardial hypertrophy, valvular insufficiency, pericardial effusion, abnormal renal echogenicity, hypoxic-ischemic cortical necrosis, ascites, pleural effusions, cardiomegaly
