Pregnancy

What is Vanishing Twin Syndrome? (and Why We Don’t Call it That)

Team Peanut5 months ago4 min read

Vanishing twin syndrome (VTS) is a type of miscarriage you can experience when you’re pregnant with multiples (twins, triplets, or more).
While you begin your pregnancy with multiple embryos in your uterus, at some point (often in the first trimester) one of the embryos stops developing as it should. Sadly, the baby dies, and its tissue is reabsorbed into the surviving baby (or babies) or your own body. It seems to have disappeared – hence the name vanishing twin syndrome.

Vanishing Twin Syndrome

But here’s the thing. Your baby hasn’t just “vanished”. Your baby has died, and you deserve to have that loss acknowledged. You deserve a chance to grieve if you need to.

That’s why, as part of our #RenamingRevolution, we’ve given vanishing twin syndrome a new name. We call a vanished twin a miscarried multiple (MM).
Let’s talk more about this kind of pregnancy loss.

Understanding vanishing twin syndrome (a miscarried multiple)

How common is vanishing twin syndrome (miscarrying a multiple)? We don’t know exactly, because it’s thought that many losses of this kind happen very early in pregnancy. That is, before the 12 week ultrasound scan has a chance to spot multiple embryos in your uterus. So it’s possible you’ve experienced this without being aware of it.

But with more women having first trimester ultrasounds now, more cases of miscarried multiples are being reported. It’s thought that around 36% of twin pregnancies and over 50% of higher multiples may be affected.

Causes of VTS (MM)

So, what causes vanishing twin syndrome (a miscarried multiple)? Sometimes, frustratingly, the cause just isn’t known. But, in many cases, it’s likely to have the same cause as most early miscarriages: something called “chromosomal abnormalities”.

It means that as your baby’s cells have been multiplying, as their body grows, something has gone wrong with their DNA (basically, their genetic blueprint). It means that they stop developing, and, sadly, they die.

It’s then that the tissue that made up their body and gestational sac (the membrane that holds your baby as they grow) is reabsorbed and they seem to “vanish”. As this is happening, your surviving baby (or babies) carries on growing and developing as normal.

How do you know if you’ve had a VT (MM)?

You might not experience any symptoms at all from miscarrying a multiple, especially if it happens very early in your pregnancy. But some of the symptoms you could have are:

Vaginal bleeding
•Abdominal cramps
•Abnormal hCG levels. (This is the hormone that’s tested to detect a pregnancy. If your doctor does a blood test and finds your hCG levels aren’t as high as they should be, that could be a sign that one of your babies has stopped developing.)

If you’re concerned about any symptoms, give your doctor a call.

A miscarried multiple is most likely to be picked up on if you have an early ultrasound scan (before the typical 12 week scan). The sonographer will see that there are two (or more) gestational sacs, and you’ll be told that you’re expecting twins or multiples.

But when you go back for your next scan, the sonographer might see one fewer gestational sac and be unable to detect the expected number of heartbeats. Though it might take a further scan to confirm, it’s around this time that you’ll find out that you’ve lost one of your babies.

This can be a painful experience with some complex emotions. Perhaps grief for your lost baby combined with relief that you still have your remaining baby (or babies). Just give yourself time to feel what you feel.

What’s the treatment for VTS (MM)?

You don’t usually need any medical treatment when you miscarry a multiple in the first trimester. And one ray of light is that most women who experience this go on to have otherwise smooth pregnancies, with their surviving babies being born healthy.

It’s possible to miscarry a multiple (have a “vanishing twin”) after the first trimester, too. (Note: this is different from losing a multiple much later in pregnancy, when the fetus is too highly developed to be reabsorbed.) In this case, your doctor might want to keep a closer eye on you for the rest of your pregnancy, because there’s a small increased risk of preterm birth, hemorrhage, and infection.

Acknowledging the loss of a miscarried multiple

We hope that you’ll be able to honor the memory of your lost baby – not as a “vanishing twin”, but as a baby who died. Maybe one day you’ll want to talk to your surviving baby, or babies, about their sibling, too. Give yourself the space you need to reflect, and be gentle with yourself.