7 Critical Symptoms of Transposition of the Great Arteries Parents Must Know

Transposition of the great arteries (TGA) is a rare but serious congenital heart defect that occurs when the two main arteries leaving the heart are reversed. In a healthy heart, the aorta connects to the left ventricle and carries oxygen-rich blood to the body, while the pulmonary artery connects to the right ventricle and carries oxygen-poor blood to the lungs. With TGA, these connections are switched, causing oxygen-poor blood to circulate through the body while oxygen-rich blood circulates back to the lungs.

This condition is life-threatening and requires immediate medical attention after birth. TGA accounts for approximately 5-7% of all congenital heart defects and affects about 1 in every 3,000-5,000 live births. Understanding the symptoms of this condition is crucial for parents and healthcare providers, as early recognition can be lifesaving. Most cases are diagnosed either before birth through prenatal ultrasound or shortly after delivery when symptoms become apparent.

The severity of symptoms can vary depending on whether there are additional heart defects present, such as ventricular septal defect (VSD) or patent ductus arteriosus (PDA), which can allow some mixing of oxygenated and deoxygenated blood. Below are the most critical symptoms that indicate transposition of the great arteries in newborns.

1. Cyanosis (Blue or Purple Skin Discoloration)

Cyanosis is the most prominent and recognizable symptom of transposition of the great arteries. This bluish or purplish discoloration of the skin occurs because oxygen-poor blood is being circulated throughout the body instead of oxygen-rich blood.

The cyanosis typically appears within the first hours or days after birth and is most noticeable in areas such as:

• Lips and tongue
• Fingernails and toenails
• Skin around the mouth
• Hands and feet

The severity of cyanosis can vary depending on the degree of blood mixing between the two circulations. Babies with additional heart defects that allow some mixing of oxygenated and deoxygenated blood may have less severe cyanosis initially. However, in isolated TGA without other defects, cyanosis can be profound and life-threatening. The blue coloration may become more pronounced during crying, feeding, or any activity that increases oxygen demand.

Healthcare providers will typically check oxygen saturation levels using a pulse oximeter. In babies with TGA, oxygen saturation readings are usually significantly below normal levels (below 85-90%), even when supplemental oxygen is provided, which is a key diagnostic indicator.

2. Rapid or Difficult Breathing (Tachypnea)

Newborns with transposition of the great arteries often exhibit rapid, shallow breathing, medically known as tachypnea. This symptom occurs as the baby’s body attempts to compensate for the lack of oxygen in the bloodstream.

Signs of respiratory distress include:

• Breathing rate exceeding 60 breaths per minute
• Flaring of the nostrils during breathing
• Grunting sounds with each breath
• Use of accessory muscles (intercostal retractions) where the skin pulls in between the ribs
• Chest rising and falling more rapidly than normal

The increased breathing effort is the body’s attempt to take in more oxygen to compensate for the low oxygen levels in the blood. However, because the problem is with blood circulation rather than lung function, increasing breathing rate does not effectively improve oxygenation. This can lead to exhaustion in the infant, particularly during feeding times when additional energy is required.

Parents may notice their baby seems to be working very hard to breathe, appearing uncomfortable or distressed. This rapid breathing pattern is usually present from birth or develops within the first few days of life, and it tends to worsen as the ductus arteriosus (a temporary fetal blood vessel) begins to close naturally.

3. Poor Feeding and Decreased Appetite

Feeding difficulties are a common and concerning symptom in babies with transposition of the great arteries. The inadequate oxygen supply to the body makes it extremely challenging for infants to coordinate the complex process of sucking, swallowing, and breathing during feeding.

Feeding-related symptoms include:

• Taking very small amounts of milk or formula
• Tiring quickly during feedings (often within a few minutes)
• Falling asleep during feeds before consuming adequate amounts
• Taking much longer than normal to complete a feeding
• Sweating excessively while feeding
• Appearing breathless or distressed during or after feeding
• Refusing the breast or bottle altogether

For a newborn, feeding requires significant energy expenditure, and babies with TGA simply don’t have the oxygen reserves to sustain this activity effectively. The increased work of breathing combined with low oxygen levels leads to rapid fatigue. Parents may notice their baby seems hungry but becomes too tired to eat adequately, creating a frustrating cycle.

This poor feeding pattern can quickly lead to inadequate caloric intake, which compounds other problems and can result in failure to gain weight appropriately or even weight loss in the first days of life.

4. Lethargy and Reduced Activity

Babies with transposition of the great arteries often appear unusually sleepy, weak, or unresponsive compared to healthy newborns. This lethargy results from insufficient oxygen delivery to the brain and other vital organs.

Signs of concerning lethargy include:

• Decreased responsiveness to stimulation
• Weak or absent crying
• Reduced movement of arms and legs
• Difficulty waking for feedings
• Lack of alertness when awake
• Decreased muscle tone (appearing “floppy”)
• Minimal eye contact or tracking

While newborns typically sleep much of the day, they should be easily arousable for feedings and show periods of alertness. A baby with TGA may seem excessively sleepy and difficult to rouse, or may wake but appear dazed and uninterested in their surroundings. The reduced activity level is the body’s way of conserving energy when oxygen supply is critically low.

This symptom can be particularly concerning because it may be mistaken for normal newborn sleepiness, especially by first-time parents. However, the combination of lethargy with other symptoms like cyanosis and breathing difficulties should always prompt immediate medical evaluation.

5. Poor Weight Gain or Failure to Thrive

Due to the combination of increased energy expenditure from rapid breathing and poor feeding intake, babies with TGA typically show inadequate weight gain or may even lose more than the expected amount of weight in the first days after birth.

Characteristics of poor growth include:

• Weight loss exceeding 10% of birth weight
• Failure to regain birth weight by two weeks of age
• No weight gain or very slow weight gain after the initial newborn period
• Decreased urine output (fewer than 6 wet diapers per day after day 5)
• Signs of dehydration such as sunken fontanelle (soft spot)
• Dry mucous membranes

The poor growth occurs because the baby’s body is using all available calories just to maintain basic bodily functions and compensate for the lack of oxygen. The increased work of breathing alone can burn significantly more calories than normal. Meanwhile, feeding difficulties prevent adequate caloric intake to support both basic metabolism and growth.

Healthcare providers closely monitor newborn weight in the hospital and during early check-ups. Failure to gain weight appropriately, especially when combined with other symptoms, is an important red flag that warrants further cardiac evaluation.

6. Rapid Heart Rate (Tachycardia)

An abnormally fast heart rate is another compensatory mechanism seen in infants with transposition of the great arteries. The heart attempts to pump more blood to deliver adequate oxygen to the body’s tissues by beating faster than normal.

Key aspects of tachycardia in TGA include:

• Resting heart rate consistently above 160-180 beats per minute in newborns
• Heart rate that remains elevated even during sleep
• Visible rapid pulsations in the chest wall or neck
• Heart rate that doesn’t decrease appropriately during calm periods

While newborn heart rates are naturally higher than those of older children and adults (normal range is typically 120-160 beats per minute), babies with TGA often have persistently elevated rates well above this range. The rapid heart rate is the cardiovascular system’s attempt to compensate for poor oxygenation by increasing cardiac output.

Healthcare providers will assess heart rate during routine examinations, but parents may also notice their baby’s heart seems to be beating very rapidly when they place a hand on the chest. This tachycardia, combined with increased work of breathing, places significant stress on the infant’s cardiovascular system and contributes to overall fatigue and poor feeding.

7. Sweating, Especially During Feeding

Excessive sweating, particularly on the head and forehead during feedings, is a subtle but important symptom of transposition of the great arteries. This sweating occurs because the baby is working extremely hard during feeding activities, similar to how adults sweat during strenuous exercise.

Sweating patterns in babies with TGA include:

• Visible beads of perspiration on the forehead and scalp
• Damp hair, especially around the hairline
• Sweating that occurs even in cool room temperatures
• Most pronounced sweating during feeding or crying
• Skin that feels clammy or cool despite sweating

In healthy newborns, sweating is relatively uncommon, as their thermoregulation systems are still maturing. However, when an infant must work hard to breathe and feed while having inadequate oxygen, the physical exertion causes sweating similar to what would occur with significant physical effort.

This symptom is often one of the more subtle signs and might be overlooked if other more obvious symptoms aren’t present. However, when a newborn consistently sweats during routine activities like feeding, especially when combined with other symptoms like rapid breathing or cyanosis, it indicates the baby’s cardiovascular system is under significant stress.

Main Causes of Transposition of the Great Arteries

Transposition of the great arteries is a congenital heart defect, meaning it develops during fetal development in the womb. While the exact cause is not fully understood in most cases, research has identified several factors that may contribute to this condition.

Genetic Factors

Although TGA is not typically inherited in a predictable pattern, genetic factors may play a role in some cases. Studies suggest that certain genetic mutations or chromosomal abnormalities may increase the risk. Some babies with TGA have other genetic syndromes, though the majority of cases occur in isolation without other genetic conditions. Families with one child affected by TGA have a slightly increased risk of having another child with a congenital heart defect, though this risk remains relatively low.

Maternal Health Conditions

Certain maternal health conditions during pregnancy have been associated with an increased risk of TGA:

• Maternal diabetes: Women with poorly controlled diabetes before and during early pregnancy have a higher risk of having babies with congenital heart defects, including TGA
• Phenylketonuria (PKU): Mothers with PKU who don’t maintain proper dietary control during pregnancy may have increased risk
• Maternal age: Some studies suggest slightly increased risk with advanced maternal age, though TGA can occur in mothers of any age

Environmental Exposures

Exposure to certain substances during pregnancy, particularly in the first trimester when the heart is forming, may increase risk:

• Medications: Certain prescription medications, particularly some anti-seizure drugs and retinoic acid derivatives
• Alcohol: Heavy alcohol consumption during pregnancy
• Viral infections: Certain viral infections during early pregnancy, such as rubella

Developmental Factors

TGA occurs when the great arteries fail to develop properly during weeks 5-8 of pregnancy. During normal heart development, the truncus arteriosus (a single vessel in the early embryo) should divide and spiral to create the correctly positioned aorta and pulmonary artery. In TGA, this spiraling process doesn’t occur properly, resulting in the arteries connecting to the wrong ventricles. The reason this developmental error occurs is not fully understood, but it likely involves a combination of genetic susceptibility and environmental factors.

It’s important to note that in most cases, no specific cause can be identified, and TGA occurs sporadically without any identifiable risk factors. Parents should understand that nothing they did or didn’t do caused their baby’s condition.

Prevention of Transposition of the Great Arteries

Because the exact cause of transposition of the great arteries is not fully understood in most cases, and it develops during early fetal development, complete prevention is not possible. However, there are several steps that women can take before and during pregnancy to reduce the risk of congenital heart defects in general:

Preconception and Early Pregnancy Care

• Achieve optimal health before pregnancy: Women planning to become pregnant should work with their healthcare provider to address any chronic health conditions, particularly diabetes, and achieve good control before conception
• Take folic acid supplements: Taking 400-800 mcg of folic acid daily beginning at least one month before conception and continuing through early pregnancy can reduce the risk of various birth defects
• Manage chronic conditions: Women with diabetes, phenylketonuria, or other chronic conditions should work closely with their healthcare providers to maintain optimal control before and during pregnancy
• Medication review: Discuss all medications, supplements, and herbal products with a healthcare provider before becoming pregnant, as some may need to be adjusted or discontinued

During Pregnancy

• Avoid harmful substances: Abstain from alcohol, tobacco, and recreational drugs during pregnancy, and avoid exposure to toxic chemicals when possible
• Prevent infections: Stay up-to-date with vaccinations before pregnancy, practice good hygiene, and avoid exposure to people with infectious illnesses
• Attend regular prenatal care: Regular prenatal visits allow healthcare providers to monitor both maternal and fetal health and identify potential problems early
• Maintain good nutrition: Eating a balanced, nutritious diet supports healthy fetal development

Early Detection

While not prevention per se, early detection through prenatal screening can help families and medical teams prepare for a baby’s needs:

• Fetal echocardiography: This specialized ultrasound can detect TGA and other heart defects before birth, allowing for proper planning and ensuring delivery occurs at a facility equipped to provide immediate cardiac care
• Routine prenatal ultrasounds: Standard prenatal ultrasounds may identify heart abnormalities that warrant further investigation
• Genetic counseling: Families with a history of congenital heart defects may benefit from genetic counseling to understand their risks

It’s crucial for expectant mothers to maintain open communication with their healthcare providers and report any concerns during pregnancy. While TGA cannot be prevented with certainty, these measures can contribute to overall healthy fetal development and ensure the best possible outcomes when congenital heart defects do occur.

Frequently Asked Questions

When do symptoms of transposition of the great arteries typically appear?

Symptoms of TGA typically appear within the first hours to days after birth. The most noticeable symptom, cyanosis (blue skin discoloration), usually becomes apparent within the first 24-48 hours of life. Symptoms may appear earlier or be more severe once the ductus arteriosus (a natural fetal blood vessel) begins to close, which normally happens within the first few days after birth. Some cases may be detected before birth through prenatal ultrasound screening.

Can transposition of the great arteries be detected before birth?

Yes, TGA can often be detected before birth through prenatal ultrasound screening. A routine prenatal ultrasound may show abnormalities that prompt further investigation with a fetal echocardiogram, a specialized ultrasound that provides detailed images of the baby’s heart structure. Fetal echocardiography can diagnose TGA as early as 18-22 weeks of pregnancy. However, not all cases are detected prenatally, and some are only diagnosed after birth when symptoms appear.

Is transposition of the great arteries a life-threatening condition?

Yes, transposition of the great arteries is a life-threatening condition that requires immediate medical intervention. Without treatment, most babies with TGA would not survive beyond the first weeks or months of life. However, with prompt diagnosis and appropriate medical and surgical treatment, the prognosis is generally good, with survival rates exceeding 90%. The key is early recognition of symptoms and rapid medical care, which is why understanding the symptoms is so important for parents and healthcare providers.

How is transposition of the great arteries different from other congenital heart defects?

TGA is unique because it involves the complete reversal of the two main arteries leaving the heart. While many congenital heart defects involve holes in the heart walls or narrowed valves, TGA involves a structural switching of the aorta and pulmonary artery. This creates two separate circulatory loops—one circulating oxygen-poor blood through the body and another circulating oxygen-rich blood through the lungs—which is incompatible with life unless there is some mixing of blood between the two circuits through other connections.

What should I do if I notice these symptoms in my newborn?

If you notice any symptoms of TGA in your newborn, especially cyanosis (blue discoloration of the skin, lips, or nail beds), rapid or difficult breathing, or extreme lethargy, seek immediate medical attention. Call emergency services or go to the nearest emergency room right away. Time is critical with TGA, and prompt evaluation and treatment can be lifesaving. Don’t wait to see if symptoms improve on their own—congenital heart defects like TGA require immediate medical intervention.

Are certain babies at higher risk for transposition of the great arteries?

TGA occurs slightly more frequently in males than females, with a ratio of approximately 2-3:1. Babies born to mothers with poorly controlled diabetes have a somewhat higher risk of congenital heart defects including TGA. There is also a slightly increased risk in families where one child has already been born with TGA or another congenital heart defect. However, most babies with TGA have no identifiable risk factors, and the condition can occur in any pregnancy.

Can babies with transposition of the great arteries appear normal at birth?

Some babies with TGA may appear relatively normal immediately after birth, especially if they have additional heart defects that allow some mixing of oxygenated and deoxygenated blood, such as a ventricular septal defect or patent ductus arteriosus. However, symptoms typically develop within the first few hours to days of life as these temporary connections begin to close. Cyanosis may not be immediately apparent in good lighting or in babies with darker skin tones, which is why medical evaluation and oxygen saturation monitoring are important for all newborns.

References:

• Mayo Clinic – Transposition of the Great Arteries
• American Heart Association – Transposition of the Great Arteries
• Centers for Disease Control and Prevention – Transposition of the Great Arteries
• Boston Children’s Hospital – Transposition of the Great Arteries
• National Heart, Lung, and Blood Institute – Congenital Heart Defects