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7 Things to Know About Twin-To-Twin Transfusion Syndrome

TTTS is uncommon but maternal-fetal experts want all mothers of twins to be aware of it.

Twin-To-Twin Transfusion Syndrome Awareness Day is Dec. 7. Even though I’m a doctor and learned about pregnancies in medical school, “TTTS” was something that wasn’t well understood. Yes, it’s well known that twin pregnancies come with more risks and challenges for mothers, babies and doctors alike, and I remembered that there’s a condition where twins “compete” in the mother’s womb. But what are the most important things for parents to know about TTTS?

Here are the seven things you should know about TTTS:

The syndrome can only occur when twins share one placenta

TTTS is a disease of the mother’s placenta and only occurs when you have twins sharing the same placenta. When that happens, the key problem is abnormal blood vessels within the placenta.

The issue with those shared vessels is that one twin gets too much blood flow and the other twin doesn’t get enough. As a result of the uneven blood distribution, one twin is at risk for problems like dehydration and development delays. The other twin, whose system is overwhelmed by too much blood, has problems with high blood pressure and heart failure — and in most cases, that’s deadly for both twins.

TTTS is rare

Twenty-five percent of twins share a common placenta, and approximately 10 percent of those twins develop TTTS.

TTTS is rare, but since two little lives are at stake, maternal-fetal experts want all mothers of twins to be aware of this syndrome. “Every mother of twins sharing a placenta should be aware of the possibility of TTTS because they need to be followed more closely during the pregnancy”, says Dr. Amanda Kalan, expert for Maternal-Fetal Medicine at Cleveland Clinic

TTTS is not the mother’s fault

TTTS is caused by abnormal connections between twins that form when the placenta first develops. This is a purely mechanical and random event that can’t be avoided. “The mother can do absolutely nothing to prevent it,” says Dr. Norman Davies, maternal fetal medicine consultant at Mayo Clinic. “There are also no known risk factors in a mother’s life that make it more likely TTTS occurs.”

These are the symptoms of TTTS

“A symptom that should alert women is a sudden increase in abdominal size,” says Davies.

The increase in belly size often goes hand in hand with rapid increases in body weight. In addition, other symptoms can include pain, tightness, or early contractions, meaning your body starts getting ready for birth too early in your pregnancy.

Early screening and diagnosis can save lives

The best course for your babies depends on the stage of TTTS and the time of diagnosis and treatment. If left untreated, 80 percent to 90 percent of twins with TTTS will die. Therefore, early screenings in mothers with twins are crucial.

Kalan: “I recommend nuchal translucency ultrasound at 11-14 weeks to screen for birth defects because this can sometimes show early signs of Twin-to-Twin Transfusion Syndrome.” That’s a special type of ultrasound used in first trimester screenings. After that initial screening, ultrasounds are typically performed every two weeks to detect signs of TTTS throughout the pregnancy until delivery.

Laser treatment: The best option we have

“For severe cases of TTTS, the best treatment we have right now is laser ablation,” explains Dr. Larry Rand, director of the Fetal Treatment Center at UCSF. Lasers pinpoint the blood vessel connections between the babies and physically cut them and seal them. You are basically separating the babies’ blood flows from each other.

According to Rand, with early detection and the laser ablation, there is a 65 percent chance of having two surviving babies and an 85 percent chance that one of the twins survives.

The No.1 question to ask when you’re told you are having twins

When Dr. Rand is giving a lecture on TTTS, he told me this is the time when he climbs on a chair so he gets everyone’s attention.

“It is not acceptable that you’re just hearing the words ‘you are having twins’. Your responsibility is to make sure you know what kind of twins you have. The most important question is: Do I have only one placenta or two?” Ask your doctor about it because with twins sharing one placenta, you are at risk for TTTS.