If you're expecting twins or higher order multiples, your pregnancy is automatically higher-risk than a singleton pregnancy.
A multiple pregnancy is considered high-risk for many reasons. When you're carrying more than one baby, there are more babies on board, more things to monitor, and more ways things can go wrong.
And if they go wrong, they can go wrong very quickly, which is why you go for more regular screening when you're carrying multiples than you would if you were carrying just a single baby.
Sometimes, parents who are expecting two or more babies in a single pregnancy are faced with an unimaginable choice: selective reduction (also called multifetal pregnancy reduction).
Selective reduction is a choice no parent makes—nor maternal fetal medicine team suggests—lightly. It's brought up in scenarios where it would lessen the associated risks for the remaining fetuses, giving them the best chance for a positive outcome at the end of the pregnancy.
It's the worst choice a parent of multiples might have to make.
But, sometimes, that agonizing choice is already made for them before they get to their next wellness appointment.
When one of the twins vanishes.
When one of the twins vanishes.
You may not have heard of this phenomenon, but a significant percentage of twin pregnancies resolve as singleton births due to a condition called Vanishing Twin Syndrome.
What is Vanishing Twin Syndrome?
According to the Cleveland Clinic, "Vanishing Twin Syndrome is a type of miscarriage that can occur during a multiple pregnancy (two or more embryos). It happens when an embryo seen on an early ultrasound no longer appears on a later one. The embryo stops growing. Typically, your body and / or the surviving embryo(s) partially or fully absorb the tissue. Vanishing Twin Syndrome usually happens during the first trimester. But it can also happen later in pregnancy."
Every pregnancy is different, but, in general, if the loss happens in the first trimester, the twin's tissue is usually reabsorbed by the mother, and no medical intervention is necessary. Sometimes, though, not all of the lost twin's tissue is reabsorbed, which can cause an infection for the mother, and that would require immediate treatment, which could include a dilation and curettage.
Expectant mothers who experience Vanishing Twin Syndrome may also have a short or insufficient cervix, which could lead to preterm delivery for the surviving twin.
With Vanishing Twin Syndrome, there's a higher risk of complications for monochorionic pregnancies (when you're carrying identical twins who share one placenta) because the loss of one twin can lead to a sudden drop in blood pressure and a shared vascular imbalance.
If the loss happens later in pregnancy during the second or third trimester, the health risks are higher for the surviving fetus. If this happens, immediate high-risk monitoring is required because the deceased twin tends to be compressed into a flattened, mummified state (called fetus papyraceus). The biggest risks to the surviving twin include neurological complications, hemorrhaging, premature birth, and low birth weight.
How common is Vanishing Twin Syndrome?
This phenomenon happens in approximately 15 to 35 percent of twin pregnancies. Thanks to early prenatal ultrasound, this condition is diagnosed much more frequently than it used to be; this is why it's so important to go to all of your prenatal appointments and not skip any, even if you're feeling fine.
Often, this condition is asymptomatic, and you don't know anything has gone wrong until the sonographer discovers an empty gestational sac without a fetal pole or heartbeat.
This isn't to instill fear in parents who are expecting multiples; it's to highlight the importance of going for regular prenatal screening throughout the entire pregnancy.
Having said this, some women who end up being diagnosed with Vanishing Twin Syndrome do experience minor symptoms of a first-trimester miscarriage, like vaginal bleeding pelvic pain, or mild cramping. If you're expecting multiples and experience any of these symptoms, head to the emergency department right away to be triaged.
One other sign that could point to Vanishing Twin Syndrome is a major slow-down in your human chorionic gonadotropin (hCG) levels.
One other sign that could point to Vanishing Twin Syndrome is a major slow-down in your human chorionic gonadotropin (hCG) levels. If your OB-GYN or healthcare team were measuring your hormone levels and they suddenly plateau or decline between appointments, especially after your medical team has indicated you're carrying multiples, this could be an indication that you've lost one twin.
While the cause of Vanishing Twin Syndrome isn't really known, there are factors that can increase your risk of this condition occurring, including:
- If you're pregnant with three or more embryos.
- If you're 35 or older.
- If you have a long-term health condition such as diabetes or lupus.
- If you have had intrauterine growth restriction (IUGR) in past pregnancies.
- If you have a subchorionic hematoma.
Losing one, loving two
When one of the embryos vanishes suddenly, it leaves one (or more, if it was a triplet or higher order pregnancy) surviving embryo that continues to grow in the womb.
The unexpected loss of one baby leaves parents reeling from an unimaginable and complex grief that is unfairly paired with the incredible joy and excitement that comes with the news that your other baby is still growing and meeting its weekly milestones.
Parents in this situation are left to mourn one child, while trying to celebrate another...
Parents in this situation are left to mourn one child, while trying to celebrate another, yet trying not to think about nor dwell on all the "what-ifs" that happen along the way.
In an instant, parents go from planning a cramped nursery for their twins to deciding what to do with the extra crib they suddenly no longer need, while wishing more than anything they still had to fit two of almost everything into their home.
Emotional support from friends and family is essential for both parents as their singleton pregnancy progresses. They may be dealing with depression as they grieve the loss of one child while trying to be joyous for the surviving twin. They say it takes a village once your babies are born, but, sometimes, you need that village long before they've arrived.
To tell or not to tell
After the surviving twin has arrived and is old enough to understand the news, parents have to weigh the pros and cons and decide whether or not to tell their child about their vanished twin.
You could never tell them about their counterpart, but as they grow, they may have an unexplainable sense that something's missing (more on this below) or an irrational fear of being abandoned.
This option also means that the parents would have to keep their feelings under wraps and hope that no one ever brings up the subject in front of the surviving twin, which is essentially impossible to control.
Or, you could tell them about the twin that was lost, framing it as a part of their unique story, rather than as a tragedy that should never be discussed.
I am a twin (who hasn't lost my twin), and this is the better option, in my opinion.
Learning about the loss might give them a lot to think about or come to terms with, but then they'll at least understand where any feelings they may already be experiencing are coming from.
Survivor's sense of loss
As a twin myself, I can tell you that twins really do share a unique bond that can keep them close for life.
In fact, they start bonding during their time in the womb. Researchers at the University of Turin and the University of Parma found that twin fetuses are aware of each other's presence and begin reaching intentionally for each other at just 14 weeks along.
It's certainly possible for those twins who survive Vanishing Twin Syndrome to experience a lifelong sense of feeling incomplete, of being robbed of the unique experience of knowing their other half, or of feeling a need to find a wholeness in others.
There's also the complex emotions that come with wondering why they survived the pregnancy and their twin didn't. Navigating these feelings can be ongoing and difficult because as much as someone might try to offer their support, the reality is they may not understand the loss in the same way as someone who's been through the same thing.
Some psychological theories suggest that losing someone you shared a womb with (even if it's before you can create conscious memories of the loss) is considered a form of early trauma and can cause inexplicable feelings of grief or loss later in life, as if a part of themself is missing.
Called Twinless Twin Syndrome, this term acknowledges the deep psychological, emotional, and physical grief a surviving twin experiences after the loss of their co-twin, whether it's from Vanishing Twin Syndrome while in utero or later on, during infancy, childhood, or adulthood.
It was a loss like this that inspired the creation of Twinless Twins Support Group International, which exists to help twins who have lost their twin—their other half—through death at any age.
Members help each other heal from and understand the loss, while offering their own support to others as they try to navigate the loss of their twin. The group was started by a twinless twin who hoped to heal from his own loss and help others like him in the process.
Navigating the unknown
There is no way to prevent Vanishing Twin Syndrome, but going for regular routine prenatal screening can help your medical team give you the best care during your multiple pregnancy.
If you find yourself in a situation where you lose one of your babies to this condition, it's important to seek support from those around you as you navigate the complex grief that is accompanied by the continuing joy of watching your surviving twin continue to grow.
Did you or someone you know experience Vanishing Twin Syndrome? How did they navigate things afterward? Let us know in the Comments section below or connect with us on Instagram to share your thoughts!
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