Twin-to-twin transfusion syndrome

Twin-to-twin transfusion syndrome
Synonyms	TTTS
Pronounce	N/A
Specialty	N/A
Symptoms	Discrepancy in amniotic fluid levels, growth discordance
Complications	Heart failure, fetal demise
Onset	During pregnancy
Duration	Until delivery
Types	N/A
Causes	Abnormal blood vessel connections in the placenta
Risks	Monochorionic twin pregnancy
Diagnosis	Ultrasound
Differential diagnosis	N/A
Prevention	N/A
Treatment	Fetoscopic laser ablation, amnioreduction
Medication	N/A
Prognosis	N/A
Frequency	N/A
Deaths	N/A

Twin-to-twin transfusion syndrome (TTTS) is a serious condition that affects monochorionic twin pregnancies, where twins share a single placenta. It occurs when there are abnormal blood vessel connections in the placenta, leading to an imbalance in blood flow between the twins. This can result in one twin (the "donor") becoming undernourished and the other twin (the "recipient") becoming overnourished.

Pathophysiology

In TTTS, the shared placenta contains abnormal vascular connections that allow blood to flow unevenly between the twins. The donor twin pumps blood to the recipient twin, leading to a volume overload in the recipient and a volume deficit in the donor. This can cause the donor twin to have reduced amniotic fluid (oligohydramnios) and the recipient twin to have excessive amniotic fluid (polyhydramnios).

Symptoms and Diagnosis

TTTS is typically diagnosed through ultrasound examination, which can reveal discrepancies in amniotic fluid levels and fetal size. The donor twin may appear smaller with a "stuck" appearance due to oligohydramnios, while the recipient twin may appear larger with polyhydramnios. Other signs include differences in bladder size and umbilical cord blood flow.

Complications

If left untreated, TTTS can lead to serious complications, including heart failure in the recipient twin due to volume overload, and growth restriction or demise of the donor twin. The condition can also lead to preterm birth and other complications associated with prematurity.

Treatment

The primary treatment for TTTS is fetoscopic laser ablation of the connecting blood vessels in the placenta. This procedure aims to interrupt the abnormal blood flow between the twins. Another treatment option is amnioreduction, which involves removing excess amniotic fluid from the recipient twin's sac to relieve pressure.

Prognosis

The prognosis for TTTS varies depending on the severity of the condition and the timing of intervention. Early diagnosis and treatment can improve outcomes, but the condition remains a significant risk factor for morbidity and mortality in monochorionic twin pregnancies.

Also see

• Monochorionic twins
• Fetoscopy
• Amnioreduction
• Premature birth

Images

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  Ultrasound image showing TTTS

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  Illustration of fetoscopic laser ablation

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  Historical depiction of twins

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