Twin-to-Twin Transfusion Syndrome


It’s exciting to find out you’re pregnant – and it can be twice as exciting to learn you’re expecting twins. Most twins are born healthy with few complications, but in rare cases, a serious condition called twin-to twin transfusion syndrome (TTTS) may occur.

TTTS happens when identical twins share a placenta, which is the organ that develops in the uterus during pregnancy to provide oxygen and nutrients to the growing fetus. Normally with identical twins, the placenta allows blood to flow evenly between the two developing babies.

In TTTS, however, the following occurs:

  • A problem with the blood vessel connection results in uneven blood flow between the twins.
  • One twin (the “donor”) becomes dehydrated, has lower blood volume, and does not produce enough urine, which results in a lack of amniotic fluid and poor growth.
  • The other twin (the “recipient”) has high blood volume and produces too much urine, which creates too much amniotic fluid and can strain the baby’s heart.
  • Without treatment, TTTS can be fatal for one or both babies, or they may have developmental disabilities or birth defects.

TTTS can develop at any point during pregnancy, and is usually first detected during prenatal ultrasound exams. The earlier in pregnancy it develops, the more serious it is.

Treatment for Twin-to-Twin Transfusion Syndrome

It is understandably frightening to learn that your twins may have TTTS. The good news is, treatments are available to help your babies survive and thrive with minimal or no complications.

Mercy’s maternal fetal medicine specialists and neonatologists will develop a personalized treatment plan to keep your babies as healthy as possible and address any negative effects on their development. Treatment depends on the severity of the condition (how unequally the blood is shared between the twins) and how far along the pregnancy is. Generally, we begin treatment as soon as possible.

  • Medication may be used in mild cases.
  • Excess amniotic fluid may be drained with a needle to slow the rate at which the condition progresses.
  • The abnormal blood vessel connections between the twins may be eliminated with laser surgery.
  • Early delivery or fetal surgery may be needed to save one or both babies if the babies are old enough to survive outside the womb.

At Mercy, we know how stressful it can be to find out your babies may be at risk. We understand the pressure of having to make treatment decisions quickly, and we will do all we can to educate, support and guide you through this challenging time.

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