Can Twins Eat Each Other in the Womb? What Really Happens

| Reviewed By Amanda Lundberg, BSN, RN

There are stories surrounding twins from the moment of conception, so it’s sometimes hard to tell the facts from fiction. Even in the womb, the experience of carrying twins presents possibilities that carrying a single baby does not. 

Can twins eat each other in the womb? Twins can’t eat each other in the womb, but this assumption comes from strange disappearing acts that can occur when you’re pregnant with twins. If you miscarry one twin while pregnant, your body may reabsorb the twin. In rare cases, the surviving twin could also absorb the miscarried twin.

Vanishing twin syndrome can occur without you even knowing you were carrying multiples. This odd phenomenon is still being studied and understood.

What Happens When One Twin Dies in the Womb

What will occur if you lose one twin in the womb depends largely on how far along you are in your pregnancy. During the first trimester, it’s possible to miscarry one twin and not even know you were pregnant with two babies. 

What Causes Miscarriage of One Twin?

The cause of most miscarriages can’t be easily identified. It’s assumed that when you miscarry one twin, it’s due to abnormalities that made the fetus nonviable. 

What Happens When One Twin Dies in the Womb?

If one twin dies in the womb during the first trimester, your body will likely reabsorb the baby, and the rest of the pregnancy will move forward normally.

If you lose a twin later in the pregnancy, your doctor will have to decide what is best for you and the surviving twin based on your unique circumstances. 

What Is Vanishing Twin Syndrome?

Vanishing twin syndrome, or VTS, is when you miscarry one twin and the other survives. VTS can happen before you even know you’re pregnant with twins or after you have seen both babies on an ultrasound. It can’t be prevented.

What Causes Vanishing Twin Syndrome?

Vanishing twin syndrome is usually due to abnormalities in one of the fetuses that make it nonviable. In other cases, there may be no known cause.

How Common Is Vanishing Twin Syndrome?

Since vanishing twin syndrome can occur before you even know you’re pregnant with twins, it’s not easy to calculate how often it happens. However, available studies show it happens in around 40 percent of twin pregnancies.

What Happens to the Vanishing Twin?

The vanishing twin is usually reabsorbed by the mother’s body. In very rare cases, the vanishing twin can be absorbed by the surviving twin. 

Vanishing Twin Impact on Surviving Twin

If the loss occurs very early in the pregnancy, there will likely be no short or long-term impact on the surviving twin.

If the loss of a twin happens further along in the pregnancy and the twins share a placenta, doctors will have to monitor the surviving twin closely to ensure he is still getting the nutrients he needs.

Surviving twins are at higher risk of low birth rate when born. In addition, they can be more likely to have complications that can result in death in the first week of life.

In some cases, the surviving twin may struggle with survivor’s guilt later in life, but this is generally not the norm.

What Is a Parasitic Twin?

A parasitic twin is one conjoined twin who stops growing in utero but stays attached to the surviving twin, often being partially absorbed, but not fully, by the remaining twin.

It’s extremely rare to conceive conjoined twins and even less likely that you will have a parasitic twin. 

The surviving twin is often born with the limbs of the parasitic twin attached to him, and surgery is required to remedy the situation. Other health problems may arise for the surviving twin after birth.

What Causes Parasitic Twins?

There is no known cause for parasitic twins, but there are theories. One is that vascular issues in the uterus can cause problems when the fetuses are trying to develop. 

What Is a Human Chimera?

A human chimera occurs when one person has two different sets of DNA. This can occur when one fraternal twin dies in the womb and the other twin absorbs the sibling’s DNA.

Fraternal twins don’t have identical DNA because of how they are conceived, so the surviving twin can have his DNA and the different DNA of the twin who passed.

Can a Fetus Really Eat Another?

No, one fetus will not and can not eat another in the womb.

Removing a Dead Twin

There are times when the passing of one twin in the womb presents a risk to the surviving twin.

In these situations, your doctor will work with you to decide when and how to remove the twin who passed. This could mean an early delivery of both babies.

Losing a Twin in the Womb

Losing a child is never easy, and you may have a lot of fear for the safety of the surviving twin if his sibling has already passed. 

How To Know if You’ve Had a Vanishing Twin

You may not know you’ve had a vanishing twin if the loss occurs before your first ultrasound.

However, if it occurs after you’ve been told you’re pregnant with twins, then you will know when one of them is no longer developing and showing up on the ultrasound. You may also have symptoms of a miscarriage.

Miscarriage of One Twin Symptoms

Cramps, bleeding, and abdominal pain may all signal the miscarriage of one twin. However, you may not have any symptoms. If concerned, call your doctor.

Prognosis for Surviving Twin

The surviving twin may have a lower birth weight and be at higher risk for problems during the first week of life. However, the long-term prognosis for most surviving twins is good.

What issues the surviving twin suffers is often determined by how far along the pregnancy was when the other twin passed and if they were sharing a placenta.

How To Deal With the Loss of a Baby

There’s no one way to deal with the grief that accompanies the loss of a child, but the grief is real.

Allow yourself time to grieve, find a support group, and talk to your doctor about any depression or anxiety you’re experiencing so you can get the help you need. 

Related Questions: 

Do Babies Eat in the Womb?

Babies get nutrients from you when they are in the womb. Nutrients pass through the umbilical cord to nourish them. They also swallow amniotic fluid while in the womb. It’s not technically what we consider eating, but it works in utero.

What Happens When One Twin Dies in Utero at 20 Weeks?

If a twin dies in utero at 20 weeks, your doctor will monitor the surviving twin closely to make sure there are no complications.

If problems do arise, your doctor will decide what option is best to make sure the surviving twin has the best outcome possible. Often, the pregnancy will continue, and you will deliver both babies when you go into labor.

Closing Thoughts

Losing a child in utero creates many complex emotions. Get the support you need to help you and the surviving twin get through the rest of your pregnancy as well as you can.