Loss of one baby in a twin or multiple pregnancy

The death of one baby before birth in a twin or higher-order pregnancy (sometimes called single intrauterine fetal death) is a distressing event. What it means for you and for the surviving baby depends a great deal on whether your babies share one placenta (monochorionic) or each have their own placenta (dichorionic). This leaflet explains why the type of placenta matters, how the surviving baby is looked after, and what to expect.

Why does the type of placenta matter?

In identical twins who share a single placenta (monochorionic), the babies’ blood circulations are joined by small blood-vessel connections on the surface of the placenta. When one baby dies, blood can suddenly flow from the surviving baby into the circulation of the baby who has died. This causes a brief but severe drop in the surviving baby’s blood pressure, which can deprive its brain and other organs of oxygen.

When each baby has its own placenta (dichorionic), there are no such connections. The surviving baby is usually not affected directly, although there may still be a higher chance of being born early.

What causes it?

In pregnancies where the babies share a placenta, the most common causes are conditions that affect how blood and nutrients are shared between them, such as twin-to-twin transfusion syndrome (TTTS), unequal growth of the babies (selective growth restriction), or twin anemia–polycythemia sequence (TAPS). A structural difference in one baby, a problem with the cord or placenta, or an infection can also be responsible, and sometimes no clear cause is found.

A very early loss of one twin in the first weeks of pregnancy (before about 14 weeks, sometimes called a “vanishing twin”) usually carries little or no risk to the other baby.

Is the surviving baby at risk?

This depends mostly on the type of placenta:

  • When the babies share one placenta, there is a risk of injury to the surviving baby’s brain or other organs, and in some cases the surviving baby may also die. Taking studies together, around 1 in 7 surviving babies do not survive, and around 1 in 4 may show signs of injury to the brain.
  • When the babies have separate placentas, the main risk is being born early; direct injury to the surviving baby is uncommon.

Could delivering my surviving baby straight away help?

Understandably, parents often ask whether delivering the surviving baby immediately would protect it. In most cases, when injury to the surviving baby happens, it happens at or very close to the moment the other baby dies — often before the loss has even been diagnosed. Delivering early does not usually prevent this injury, and it adds the risks of being born premature. For this reason, unless the pregnancy is already close to term, your team will often recommend continuing the pregnancy with close monitoring rather than delivering right away.

How will my surviving baby and I be monitored?

You will be cared for in a specialist fetal-medicine center. Monitoring may include:

  • A Doppler ultrasound of blood flow in the surviving baby’s brain (the middle cerebral artery peak systolic velocity, or MCA-PSV) to check for anemia (a low blood count).
  • Regular ultrasound scans to follow the baby’s growth and wellbeing, usually every 2–4 weeks.
  • A detailed scan of the baby’s brain, and often a fetal MRI scan, usually about 4–6 weeks after the loss, because some changes take time to become visible.

If all is well, your team will usually aim to continue the pregnancy and plan birth at around 34–36 weeks, after giving medication (steroids) to help the baby’s lungs mature.

Are there treatments for the surviving baby?

If the surviving baby is found to be anemic, a blood transfusion given to the baby while still in the womb (intrauterine transfusion) may be considered. This can correct the anemia, but at present there is not enough evidence to know whether it reduces the chance of long-term problems.

What is the long-term outlook?

The outlook depends on the type of placenta, how many weeks the pregnancy had reached when the loss happened, whether the surviving baby became anemic, and what the brain scans show. When the scans are reassuring, the outlook is more favorable. Because some difficulties can appear later, follow-up of the child’s development through infancy and early childhood — usually at least to around 2 years of age — is recommended.

Looking after yourself

Losing one baby while still carrying another is uniquely difficult, and grief and worry often come together. Support is available, and your team can refer you to bereavement counselling, perinatal mental-health services, or support groups. Please do not hesitate to ask for it.

 

What other questions should I ask?

  • Do my babies share one placenta, or do they each have their own?
  • What is likely to have caused the loss of one of my babies?
  • What are the risks to my surviving baby?
  • How, and how often, will my surviving baby be monitored?
  • When and where is it best for me to give birth?
  • What support is available for me and my family?

Last updated June 2026

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