Introduction to TTS (or TTTS)

Melissa pointed out to me that Twin-to-Twin Transfusion Syndrome is more typically abbreviated "TTTS" than "TTS." I've seen both, though, and prefer the latter. Our keyboard will last longer if we're economical with our "T's."

The purpose of this post is to introduce TTS. Rather than reinvent the wheel, we'll point you to a few established Internet sites on the subject and simply add our commentary. This is a good place to start:

http://www.tttsfoundation.org/what%20is%20ttts.html

If you don't have time to read the full page, here's a brief intro:

Identical twins share a single placenta. Virtually all share blood vessels (veins and arteries) in the placenta. Usually, these interconnections aren't a problem. TTS is a "disease" of the placenta (interesting word-choice, but it's found across all of the 'net sites I could find on the subject, so it must be the right one) that results in the twins sharing the placenta unequally. One twin, called the "donor twin," sends along most of the blood (and thus the nutrients) available there to the other, called the "recipient." In our case, Spencer is the donor and Micah the recipient.

Possible results of the blood-sharing imbalance are these:

- Unequal distribution of amniotic fluid and, as a result, available space in mom's tummy. In our case it's about an 80-20 split. Micah lounges in an Olympic pool while Spencer is making do with a wading puddle. It's for this reason that the "donor" twin is sometimes also called the "stuck" twin: he's pressed against the wall in more or less the same place regardless of how Melissa is positioned. The recipient moves about in response to gravity when Melissa shifts, responding to gravity.
- The donor twin can wind up undernourished and dehydrated.
- The recipient twin can suffer congestive heart failure as his heart works harder than usual to manage the excess bloodflow through his body and fluid accumulates around his heart.


Left unreated, TTS poses a tremendous risk of mortality for one or both twins. You'll find a range of numbers out there; the stat we've seen most often indicates that there's a 90% chance of both twins passing away in utero without treatment. With treatment, the odds improve. They're still not stellar, but they're better. More about this when we explain the treatment options later.

I borrowed the image at right from the Fetal Care Center of Cincinnatti's excellent website about one of the treatment options. It's found at http://www.fetalcarecenter.org/medicine/fetal-surgery/surgery-ttts.htm.