Fetal Conditions Affecting Twins

There are certain types of fetal abnormalities specific to twins. More often than not, these abnormalities affect more than one twin. Our team works with your family to create specialized care plans to ensure safety and best outcome for your babies.

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Conditions we treat:

Identical twins who share a placenta are known as monochorionic twins. These twins share a network of blood vessels that are responsible for supplying oxygen and nutrients essential for their development in the wound. Sometimes, complications can arise in monochorionic twin pregnancies that require intervention. These include:

Twin-Twin Transfusion Syndrome (TTTS): 

Twin-twin transfusion syndrome (TTTS) occurs when there is uneven blood flow between twins who share a placenta (monochorionic twins). This uneven blood flow is caused by abnormal blood vessel connections forming in the placenta. 

The “donor twin” pumps blood to the “recipient twin,” affecting each twin in different ways. On one hand, the donor twin may become dehydrated, unable to produce as much urine as it should and leading to a decreased amount of amniotic fluid. This causes problems in fetal development, including potential organ failure. On the other hand, the extra fluid that the recipient twin receives can put extra strain on the recipient twin’s heart, increasing the risk for heart failure. The recipient twin may also produce too much urine, resulting in an enlarged bladder and too much amniotic fluid.

Twin anemia-polycythemia sequence (TAPS):

Twin anemia-polycythemia sequence (TAPS) is a form of twin-twin transfusion syndrome (TTTS). Similar to TTTS, twins affected by TAPS have an unequal blood flow, except the difference is that the placental connection in TAPS is smaller. This is due to the joining of smaller artery-to-vein vessel connections, otherwise known as AV anastomoses.

TAPS causes the recipient twin to receive more red blood cells than the donor twin. The donor twin is at risk for anemia, or progressive blood loss, while the recipient twin is at risk for polycythemia, or increasing blood count leading to thicker, sluggish blood. This puts the recipient twin at risk of blood clots, or thrombosis.

TAPS can either occur spontaneously or after a laser surgery treating TTTS.