Definition

Conjoined twins, also known as Siamese twins, refer to twin babies whose bodies are physically connected at certain parts. The term "Siamese twins" originates from the famous conjoined twins Chang and Eng Bunker, who were connected at the chest and came from Siam (now Thailand). They gained worldwide recognition by performing in circuses across America and Europe during the 1800s.

Conjoined twins represent a very rare condition that poses numerous complications during pregnancy, childbirth, and even after birth. This phenomenon occurs in approximately 1 in every 50,000 pregnancies. Most conjoined twins do not survive long, as the organs that are fused are often vital for life. The incidence of conjoined twins is notably higher in regions such as India and Africa, with a survival rate of around 25%.

There are several types of conjoined twins, each with its own specific name and characteristics:

• Omphalopagus: Twins connected at the abdomen
• Thoracopagus: Twins connected at the chest
• Cephalopagus: Twins connected from the head to the navel, facing each other
• Craniopagus: Twins connected at the head only
• Ischiopagus: Twins connected at the pelvis, facing each other
• Parapagus: Twins connected at the pelvis but not facing each other, side by side
• Pygopagus: Twins connected at the sacrum (tailbone), with their backs to each other
• Rachipagus: Twins connected at the spine

Causes

The exact cause of conjoined twins remains unknown. However, it is theorized that conjoined twins occur during days 12 to 14 after fertilization, when the embryo fails to completely separate. The precise reasons behind the failure of embryonic division during fertilization are still unclear.

Risk Factor

No specific factors have been identified that increase or decrease the risk of conjoined twins. A previous pregnancy with conjoined twins does not increase the likelihood of conjoined twins in subsequent pregnancies.

Symptoms

There are no specific symptoms associated with conjoined twins during pregnancy. As with other twin pregnancies, the uterus and abdomen of the mother may appear larger than expected for the gestational age. Apart from this, there are no distinct symptoms, and the pregnancy may present similarly to a normal one, with symptoms such as nausea (with or without vomiting), missed periods, breast tenderness, fatigue, and increased frequency of urination. Further diagnostic evaluation is necessary to determine whether a pregnancy involves conjoined twins.

Diagnosis

Routine prenatal examinations are essential for diagnosing conjoined twins. The diagnostic process involves anamnesis (patient-doctor interviews), physical examinations, and additional diagnostic tests.

During anamnesis, the doctor will inquire about the gestational age, the date of the last menstrual period, any symptoms experienced during pregnancy, pregnancy history, sexual behavior history, menstrual history, past medical history, family medical history, medication use, and daily lifestyle and activity patterns.

Following this, the doctor will conduct a physical examination. In pregnant women, this includes checking vital signs such as blood pressure, body temperature, respiratory rate, and pulse. The doctor may also palpate the abdomen to assess the position of the fetus, estimate the number of fetuses, measure the size of the uterus, and estimate fetal weight.

The doctor may also recommend additional tests, such as an ultrasound, to examine the morphology or structure of the fetus in detail. Ultrasound can also detect anatomical abnormalities in the fetus, providing the most accurate results during the first trimester.

Therefore, pregnant women are advised to undergo regular prenatal checkups and not to worry about the effects of ultrasound, as it uses sound waves that are very safe for both mother and fetus. The doctor may also suggest more advanced tests like MRI if there are specific concerns.

Management

Generally, the management of conjoined twins can be categorized into three approaches:

• No surgical intervention: If separating the conjoined twins poses a life-threatening risk, surgery may be avoided, and treatment will focus on addressing any symptoms or complaints.
• Immediate surgery: If the doctor assesses that one or both of the conjoined twins require surgery to save their lives, immediate surgery may be performed after birth.
• Delayed surgery: If the conjoined twins are stable and likely to survive for a longer period, surgery may be postponed until they are older to allow their organs to mature. This typically occurs between 9 and 12 months of age, and in some cases, the twins can survive into adulthood.

Complications

Complications associated with conjoined twins can arise both during pregnancy and in the condition of the twins themselves. These complications include:

• The mother may require a cesarean section for delivery
• Increased risk of premature birth
• One or both twins may die at birth or shortly after
• The health of the conjoined twins may be compromised, with increased risks of respiratory or cardiac issues
• Death due to the inability of vital organs to function properly in one or both twins
• Hemorrhage in the conjoined twins due to surgical separation

Prevention

Since the causes and risk factors are not well understood, there are no specific methods to prevent conjoined twins. However, the following tips can be helpful when planning and during pregnancy:

• Regular monthly prenatal checkups with a midwife or obstetrician
• Taking folic acid supplements to prevent neural tube defects in the fetus
• Taking iron supplements to prevent anemia and malnutrition during pregnancy
• Ensuring a balanced diet with adequate nutrition, including vegetables, fruits, and high-protein foods
• Drinking at least 1.5 liters of water daily to stay hydrated
• Avoiding alcohol consumption and exposure to cigarette smoke during pregnancy
• Reducing excessive sugar and caffeine intake from coffee and tea
• Educating oneself by attending pregnancy classes and reading about conjoined twins before and during pregnancy

When to See a Doctor?

If conjoined twins are suspected during pregnancy, your doctor will closely monitor and inform you of the situation. Therefore, it is crucial to visit the doctor and undergo monthly prenatal checkups to detect any potential issues early, allowing for better management and preparation by the patient, specialists, and medical staff

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