What is the cause of Vanishing Twin Syndrome?

Many women who conceive naturally may not even be aware that at one point, very early in their pregnancy, they were carrying twins! Now, if you conceived via IVF and were monitored regularly after your transfer then you would be very aware if one, two or more sacs were seen and just what the condition of each might be...is there a fetal pole?  a heart beat? empty? However, what can happen is that during one ultra sound a twin pregnancy is pronounced and by the next there is only one heartbeat on the monitor. This devastating news to those in love with the idea of having twins is referred to as the Vanishing Twin Syndrome. (Others may sigh in relief)

 

I have posted some more "technical" information below but first I would like to share with you the fact that I had a Vanishing Triplet! My very first surrogacy, and second IVF attempt, we had transferred 3 embryos. After receiving the very high beta numbers we scheduled our first US at 7 weeks. We were in for a shock! Having thought that it could only be twins...as we were told that not all 3 embryos were the best, we saw 3 sacs on the monitor! And 2 of those had healthy heart beats. The third, however, seemed smaller. Perhaps a late implanter? Maybe...but now we had to schedule a 2nd US to see what that 3rd sac would do as my IP's had no intention of raising triplets. We had agreed, you see, on selective reduction for anything over twins.

 

When I returned, on my own the next time, it was obvious that the 3rd sac was already starting to dissipate and the two other sacs (both girls, we came to find out later) were healthy and growing at a normal rate!

 

If we had conceived naturally, there most likely would never have been a Beta test, there might have been no ultra sounds until the 20th week...where we would have seen twin girls, healthy and strong....we would have never been aware of that third sac.

 

Sharon

www.InfertilityAnswers.net

 

What is the cause of Vanishing Twin Syndrome?

Vanishing twin syndrome was first recognized in 1945. Vanishing twin syndrome is when one of a set of twin/multiple fetuses disappears in the uterus during pregnancy. This is the result of a miscarriage of one twin/multiple. The fetal tissue is absorbed by the other twin/multiple, placenta or the mother. This gives the appearance of a “vanishing twin”.

How is Vanishing Twin Syndrome identified?

Before the use of ultrasound, the diagnosis of the death of a member of a multiple pregnancy was made through an examination of the placenta after delivery. Today, with the availability of early ultrasounds, the presence of twins or multiple fetuses can be detected during the first trimester. A follow-up ultrasound may reveal the “disappearance” of a twin.

For example, a woman may have an ultrasound at 6 or 7 weeks gestation. The doctor identifies two fetuses and the woman is told she is having twins. When the woman returns for her next visit, only one heartbeat can be heard with Doppler. A second ultrasound is conducted and only one fetus is observed.

Sometimes a woman may have symptoms that would indicate a miscarriage, yet, with an ultrasound, a single baby is found in her uterus.

Vanishing twin syndrome has been diagnosed more frequently since the use of ultrasonography in early pregnancy. A conservative estimate of frequency is that vanishing twin syndrome occurs in 21-30% of multi fetal pregnancies. Research from a European series of pregnancies associated with assisted reproductive technology (ART) show that 10-15% of singleton births were initially twin gestations.

 

Comments

[vetaler]

i first came across VT a few years ago - and it seemed to explain what happened during my pregnancy with my youngest daughter 23 years ago. no US scans in the part of europe i lived in then unless there was a 'reason' ... that reason came in juli 1985 when i was 7 months pregnant and bleeding. the baby hung on in there for another 4 weeks and was born a month early, and very small, in august. i later learned that this was consistent with her being the survivor of VT - in march i had suffered what was then thought of as being a threatened miscarriage... cramps and bleeding. but the pregnancy continued...
the placenta was damaged - this much was noted by the midwife after the baby was born - but was that due to the july occurrence or the march event?
oh yes - i am rhesus negative and my then husband rhesus positive and i did smoke during that pregnancy... all pointers towards VT syndrome...
no one can say for certain now, but i feel fairly certain that i was expecting twins then...

[Silver]

Thanks for stopping by my blog.

This post hit close to home as I lost my daughter's twin early on. There was two heart beats at 6 weeks, but by 10 only one. The loss still bothers me after seeing that 2nd heart beat.

[Martha]

Good clinical overview. Visiting from ILCW.

[Kristin]

I just wanted to say thank you for your surrogacy work. I haven't had to use a surrogate but I do know someone who did and she is forever grateful to that wonderful woman.

ICLW

[Seriously?]

Hello, here from ICLW. My mother had fertility treatments in 1974/75 for my brother. She had vanishing twins with him. The second one was gone at her 8 week ultrasound. I always wonder if she took that as hard as her few m/c.