Introduction
Conjoined twins, a highly uncommon occurrence, are twins who are physically joined together. This unique situation presents numerous complications throughout the course of pregnancy, delivery, and postnatal care. It is occasionally referred to as Siamese twins, in honor of the renowned conjoined twins Chang and Eng Bunker from Thailand (formerly known as Siam), these individuals gained fame as performers in Europe and America during the 1800s.
Due to advancements in modern medicine, some conjoined twins can now undergo surgical separation. However, there are cases where twins remain connected for the entirety of their lives. The majority of conjoined twins require ongoing medical attention to effectively manage their long-term health.
What Are Conjoined Twins?
Conjoined twins are babies who are physically linked at birth. This happens when an early embryo splits into two individuals. The etiology of this illness is unknown, however, it is most likely caused by the splitting or fusing of extremely early-stage embryos shortly after fertilization. Conjoined twins are usually identical, and roughly two-thirds of them are assigned female at birth. While many conjoined twins die, breakthroughs in surgery and technology have increased survival rates, and depending on the location and amount of shared organs, as well as the medical team's ability, some can be surgically separated.
Why Do Conjoined Twins Happen?
Monozygotic twins, also known as conjoined twins, originate from a single fertilized egg that divides into two embryos. Normally, this division results in identical twins. However, in extremely rare cases, the embryos do not fully separate, and the reasons for this are not yet fully understood by scientists. It is believed that the eggs either fail to separate completely or reattach shortly after separating.
How Common Are Conjoined Twins?
Conjoined twins are an extremely uncommon occurrence. According to medical professionals, the likelihood of conjoined twins being born is estimated to be only 1 in 200,000 live births. Unfortunately, more than half of pregnancies involving conjoined twins end in either miscarriage or stillbirth. Moreover, a significant number of conjoined twins pass away shortly after being born. In fact, due to the complex nature of their shared anatomy, many conjoined embryos are unable to survive. Up to 60 percent of conjoined twins are either stillborn or do not survive long after delivery.
What Happens if Someone Gets Pregnant With Conjoined Twins?
Doctors typically identify conjoined twins through the use of ultrasound during the first or second trimester of pregnancy. In such cases, the doctor will recommend further examinations to gain a better understanding of the twins' physical connection and the organs they may share. Expectant parents will receive guidance from doctors regarding the potential outcomes and challenges associated with the pregnancy and delivery of conjoined twins. In situations where the twins' condition is incompatible with sustaining life, parents will be faced with the decision of how to proceed. During this time, doctors will provide information about available options and ensure the provision of optimal care for the family. The delivery of most conjoined twins necessitates a cesarean section. Following the birth, a specialized medical team will be readily available to provide immediate care for the twins.
What Are the Types of Conjoined Twins?
Conjoined twins can exhibit various types of attachments, each unique in its own way. The manner in which their bodies are connected can differ significantly:
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Thoracopagus (Chest Attachment): In this type, the twins face each other and are joined in the area of the ribcage. Typically, they share a single heart and may also have a shared liver. Additionally, it is common for them to possess four arms and four legs.
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Omphalopagus or Xiphopagus (Abdominal Attachment): Here, the twins also face each other but are connected below the sternum. They may share a liver, a biliary tract, and an upper digestive tract. Similar to thoracopagus twins, they often have four arms and four legs.
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Pygopagus (Lower Back Attachment): In this case, the twins are joined back-to-back and may share genital organs, a urinary tract, a lower digestive tract, as well as the bones and nerves of the lower body. While it is uncommon, they might possess two or three legs.
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Ischiopagus (Pelvic Attachment): The twins are connected at the pelvis and may or may not face each other. They might share a liver, biliary tract, parts of the upper and entire lower digestive tract, as well as the genital and urinary systems. It is possible for them to have two or three legs.
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Craniopagus (Head Attachment): In this type, the twins are connected at the top of the skull. Although their brains are usually connected, there are instances where this is not the case.
How Is the Diagnosis of Conjoined Twins Made?
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Prenatal imaging tests, such as ultrasound and MRI, can detect conjoined twins as early as 12 weeks into the pregnancy.
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If imaging tests reveal conjoined twins, medical professionals will assess potential complications and develop a plan to address them during delivery.
Is It Possible to Separate Conjoined Twins?
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Surgery to separate conjoined twins is not always possible, especially if they share vital organs like the heart. Doctors typically wait a few months to a year after birth to assess if separation is feasible. This waiting period allows the twins to grow stronger and for doctors to better understand their bodies before proceeding with surgery.
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In certain cases, emergency separation surgery may be necessary for conjoined twins. If one twin passes away or experiences a life-threatening medical event, the surgery could potentially save the other twin's life.
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Elective separation surgery for conjoined twins is a complex procedure. Some conjoined twins choose not to undergo separation surgery and continue to live as adults joined together. As they grow up, these twins may require accommodations for transportation and housing. However, some pairs are able to lead independent lives, pursuing careers and forming relationships.
Conclusion
Conjoined twins are a unique type of identical twins who are not completely separate from each other. The diagnosis is determined using ultrasound technology. If there is a suspicion of the diagnosis in the early stages of pregnancy, a follow-up scan is required to confirm it, as there is a chance of an incorrect diagnosis during the early gestational period. Separating conjoined twins is a complex and difficult task that involves meticulous planning and the collaboration of various specialists, especially surgical experts.
