Conjoined twins can be diagnosed using routine ultrasound as early as 7 to 12 weeks of pregnancy. More-detailed ultrasounds and tests that use sound waves to produce images of the babies' hearts (echocardiograms) can be used about halfway through pregnancy. These tests can better determine the extent of the twins' connection and the functioning of their organs.

If an ultrasound detects conjoined twins, a magnetic resonance imaging (MRI) scan may be done. The MRI may provide greater detail about where the conjoined twins are connected and which organs they share. Fetal MRI and fetal echocardiography assist with planning for care during and after pregnancy. After birth, other tests are done to help identify the body structure and organ function of each twin and what is shared.


Treatment of conjoined twins depends on their unique situation — their health issues, where they're joined, whether they share organs or other vital structures, and other possible complications.

Monitoring during pregnancy

If you're carrying conjoined twins, you'll likely be closely monitored throughout your pregnancy. You'll likely be referred to a maternal and fetal medicine specialist in high-risk pregnancy. When needed, you may also be referred to other pediatric specialists in:

  • Surgery (pediatric surgeon)
  • Urinary system, such as kidneys and bladder (pediatric urologist)
  • Bone and joint surgery (pediatric orthopedic surgeon)
  • Surgical repair and correction (plastic and reconstructive surgeon)
  • Heart and blood vessels (pediatric cardiologist)
  • Heart and blood vessel surgery (pediatric cardiovascular surgeon)
  • Care of newborn babies (neonatologist)

Your specialists and others on your health care team learn as much as possible about your twins. This includes learning about their body structures, their ability to perform certain activities (functional capabilities) and the likely outcome (prognosis) to form a treatment plan for your twins.


A C-section is planned ahead of time, often 3 to 4 weeks before your due date.

After your conjoined twins are born, they're fully evaluated. With this information, you and your health care team can make decisions regarding their care and whether separation surgery is appropriate.

Separation surgery

If a decision is made to separate the twins, separation surgery is usually done around 6 to 12 months after birth to allow time for planning and preparation. Sometimes an emergency separation may be needed if one of the twins dies, develops a life-threatening condition or threatens the survival of the other twin.

Many complex factors must be considered as part of the decision to do separation surgery. Each set of conjoined twins presents a unique set of issues due to differences in body structure and function. Issues include:

  • Whether the twins share vital organs, such as the heart
  • Whether the twins are healthy enough to withstand separation surgery
  • Odds of successful separation
  • Type and extent of reconstructive surgery needed for each twin after separation
  • Type and extent of functional support needed after separation
  • What challenges the twins face if they stay joined together

Recent advances in imaging before birth, critical care and anesthetic care have improved outcomes in separation surgery. After separation surgery, pediatric rehabilitation services are crucial to help the twins develop properly. Services may include physical, occupational and speech therapies and other assistance as needed.

If surgery isn't an option

If separation surgery isn't possible or if you decide not to have the surgery done, your team can help you meet the medical care needs of your twins.

If the circumstances are grave, medical comfort care — such as nutrition, fluids, human touch and pain relief — is provided.

More Information

Coping and support

Learning that your unborn twins have a major medical issue or life-threatening condition can be devastating. As a parent, you struggle with difficult decisions for your conjoined twins and the uncertain future. Outcomes can be difficult to determine, and conjoined twins who survive sometimes face tremendous obstacles.

Because conjoined twins are rare, it may be difficult to find supportive resources. Ask your health care team if medical social workers or counselors are available to help. Depending on your needs, ask for information on organizations that support parents who have children with physical conditions that limit their abilities or who have lost children.

Preparing for your appointment

If you're pregnant with conjoined twins, you'll be referred to a team of specialists to help guide you and create a treatment plan for your twins. Here's some information to help you get ready and what to expect from your team.

What you can do

Before your appointment:

  • Consider taking a family member or friend along. Sometimes it can be hard to remember all the information provided during an appointment. Someone who comes with you may remember something that you missed or forgot.
  • Make a list of questions to ask your health care provider. List your questions from most to least important to make the most of your appointment time.

Some basic questions to ask include:

  • What tests do my twins need?
  • Where are my twins joined and what, if any, body organs do they share?
  • What is the best treatment plan?
  • Is separation an option? What is the likely outcome with separation?
  • How many separation surgeries have you and your team performed, and how many have been successful? How does that compare with the national success rate?
  • What are the alternatives to the treatment approach that you're suggesting?
  • What specialists should be involved in the health care team?
  • Are there any other specialists I should meet with?
  • Where can I find support for my family?
  • Are there printed materials that I can have? What websites do you recommend?
  • If I choose to have more children, is there a chance they may also be conjoined?

Don't hesitate to ask other questions during your appointment.

What to expect from your doctor

Your health care provider and other members of your health care team review your conjoined twins' tests and exam results and discuss options with you. Together with your team, you can make decisions for your twins' treatment and care.

Dec. 16, 2022
  1. Mian A, et al. Conjoined twins: From conception to separation, a review. Clinical Anatomy. 2017; doi:10.1002/ca.22839.
  2. Greco PS, et al. Conjoined twins: An obstetrician's guide to prenatal care and delivery management. Journal of Perinatology. 2021; doi:10.1038/s41372-021-01107-5.
  3. Sager EC, et al. Conjoined twins: Pre-birth management, changes to NRP, and transport. Seminars in Perinatology. 2018; doi:10.1053/j.semperi.2018.07.008.
  4. FAQs: Multiple pregnancy. American College of Obstetricians and Gynecologists. https://www.acog.org/womens-health/faqs/multiple-pregnancy. Accessed May 19, 2022.
  5. Wang SS, et al. Double trouble: Complications in twin pregnancies. Ultrasound Quarterly. 2020; doi:10.1097/RUQ.0000000000000484.
  6. Frawley G. Conjoined twins in 2020 ⸺ State of the art and future directions. Current Opinion in Anesthesiology. 2020; doi:10.1097/ACO.0000000000000864.
  7. Arnold J, et al. Introduction: Unique challenges in the care of conjoined twins. Seminars in Perinatology. 2018; doi:10.1053/j.semperi.2018.07.007.
  8. Cugini K, et al. Therapy services and specialized devices for conjoined twins: Unique challenges with conjoined twins and the importance of physical and occupational therapy. Seminars in Perinatology. 2018; doi:10.1053/j.semperi.2018.07.010.
  9. Thomas A, et al. An ethically-justifiable, practical approach to decision-making surrounding conjoined-twin separation. Seminars in Perinatology. 2018; doi:10.1053/j.semperi.2018.07.016.
  10. Anca FA, et al. Special forms in twin pregnancy ― Asymmetric conjoined twins. Journal of Medicine and Life. 2015;8:115.
  11. Ruffo G, et al. Fetus-in-fetu: Two case reports. Journal of Maternal-Fetal & Neonatal Medicine. 2019; doi:10.1080/14767058.2018.1449207.
  12. Schenone MH (expert opinion). Mayo Clinic. June 8, 2022.


Associated Procedures