It is possible to miscarry one twin in a twin pregnancy. This is known as vanishing twin syndrome and occurs when one embryo dies in the womb while the other continues developing. Vanishing twin syndrome is actually more common than most people realize, occurring in up to 30% of twin pregnancies.
What causes vanishing twin syndrome?
There are a few potential causes of vanishing twin syndrome:
- Chromosomal defects – One embryo may have genetic abnormalities that prevent proper development.
- Improper implantation – One embryo fails to properly implant in the uterus.
- Discrepant growth – One embryo receives an unequal share of resources and cannot grow at the same rate.
- Vanishing twin syndrome – One embryo essentially ‘vanishes’ and is reabsorbed by the mother’s body.
The exact cause is often unknown, but vanishing twin syndrome occurs very early in pregnancy, usually within the first trimester. After one embryo dies, the tissue is typically reabsorbed by the placenta and vanishes without a trace over time.
Signs and symptoms
Often there are no signs or symptoms when one twin vanishes. Some women may experience:
- Bleeding in the first trimester
- Cramping or pelvic pain
- A change in pregnancy symptoms like nausea or breast soreness
- A decrease in the level of hCG (pregnancy hormone)
An early ultrasound may reveal two gestational sacs or embryos initially, followed by only one in subsequent scans. However, since most women don’t get ultrasounds until later in the first trimester, many vanishings go undetected.
Potential complications
Vanishing twin syndrome does not usually cause complications in the surviving twin. Risks include:
- Preterm labor and delivery
- Low birth weight
- Congenital abnormalities – slightly higher risk compared to singletons
- Excess amniotic fluid (polyhydramnios)
- Incorrect due date if early ultrasound dates were used
However, most of the time there are no long-term risks associated with vanishing twin syndrome. The surviving baby typically continues to develop normally.
Management and care
If vanishing twin syndrome is suspected, your doctor will monitor you and the remaining fetus closely. An ultrasound can confirm if one twin has been lost. You may need more frequent ultrasounds to track fetal growth and development.
Make sure to take good care of yourself during pregnancy as you normally would. Eat well, avoid substances and alcohol, take prenatal vitamins, and get plenty of rest. Staying healthy gives the surviving twin the best chance to grow.
Talk to your doctor about any concerns such as signs of preterm labor. Emotional support may help some women cope with feelings of loss or guilt.
Outlook and recovery
The prognosis for the surviving twin is usually excellent. The risk of miscarriage drops significantly after the first trimester. The remaining baby typically continues to grow and develop normally.
Your doctor will be able to provide the best guidance regarding your individual prognosis. Make sure to attend all prenatal visits so your pregnancy can be monitored closely.
Physically, most women recover well after losing one twin. The vanished embryo is reabsorbed by the body. The remaining gestational sac may stay or gradually disappear as well. Your hCG levels will drop if they were elevated.
Emotionally, it may take longer to recover from the loss. Give yourself permission to grieve, and seek counseling if you are struggling with anxiety, depression, or feelings of guilt.
Prevention
There is no known way to prevent vanishing twin syndrome, since the cause is often chromosomal abnormalities or other factors out of the mother’s control. Early ultrasounds sometimes reveal twins that later vanish, but no intervention can prevent the spontaneous loss.
When to see a doctor
Contact your doctor right away if you have:
- Bleeding or cramping in the first trimester
- Changes in pregnancy symptoms
- Signs of preterm labor like contractions, pelvic pressure, or fluid leaking
Talk to your doctor about any concerns related to a potential vanishing twin. Your obstetrician will be able to provide the best care and monitoring during your pregnancy.
Coping and support
Learning that one twin has vanished can be emotionally difficult. Many women feel a sense of loss, grief, emptiness, or guilt. Know that these emotions are normal and it is ok to take time to process the news.
Talking to your partner, friends, family, or doctor may help. Counseling provides a safe space to voice fears and explore the grieving process. Joining a support group connects you with other moms who have experienced vanishing twin syndrome.
Focusing on taking good care of yourself and your surviving baby are also positive coping strategies. Getting rest, eating nutrient-rich foods, exercising, and decreasing stress can have lifelong benefits for you and your child.
Conclusion
Vanishing twin syndrome occurs in up to 30% of twin pregnancies when one embryo is lost in the first trimester. Common causes are chromosomal issues, problems implanting, or uneven growth. Signs can include bleeding, cramping, change in symptoms, or an ultrasound showing two gestational sacs then only one.
While the loss of one twin can be emotionally difficult, the prognosis for the remaining baby is typically very good. With close monitoring, the surviving twin will often continue to grow and thrive. Talk to your doctor right away about any concerning symptoms, and take care of your emotional health as well during this potentially challenging time.
| Key Points | Details |
|---|---|
| Definition | Spontaneous loss of one twin early in a multiple pregnancy |
| Incidence | Up to 30% of twin pregnancies |
| Causes | Chromosomal abnormalities, improper implantation, unequal growth |
| Signs | Bleeding, cramping, change in symptoms, empty gestational sac on ultrasound |
| Risks | Emotional loss, slightly higher chance of preterm birth or low birth weight for surviving twin |
| Management | Close monitoring, normal prenatal care, emotional support |
| Prognosis | Usually excellent for surviving twin |