NBC News White House Correspondent Carol Lee recently shared an update about her son Monty after her harrowing birth experience. Monty –now crawling, smiling, and asserting his strong will – was diagnosed with transposition of the great arteries (TGA) in utero and underwent open-heart surgery within days of his birth.
TGA (or "transposition of the great vessels") is a congenital heart defect that develops before birth. In a normal heart, two large arteries carry blood out of the heart, the pulmonary artery and aorta (sometimes called the "great vessels" or "great arteries"). In children with TGA, these arteries are connected to the heart abnormally. The aorta is attached to the right-sided pumping chamber (ventricle) instead of the left. Instead, the right pulmonary artery is attached to the left-sided pumping chamber (ventricle). The prevalence of TGA in the United States is estimated to be 4.7 per 10,000 live births.
Signs of TGA may be detected before birth during a routine pregnancy ultrasound or after birth if the baby has blue skin, a weak pulse, or trouble breathing. Ultrasounds that primarily focus on a four-chamber view of the heart may miss TGA. Prenatal detection is increased when the outflow tracts are evaluated to determine whether or not the great arteries cross normally. Practice guidelines for sonographic screening of the fetal heart available from the International Society for Ultrasound in Obstetrics and Gynecology and from a collaboration of the American Institute of Ultrasound in Medicine, American College of Radiology, American College of Obstetricians and Gynecologists, Society for Maternal-Fetal Medicine, and Society of Radiologists in Ultrasound, include views of the four chambers and ventricular outflow tracts as standard for cardiac evaluation. A fetal echocardiogram may be recommended. A fetal echocardiogram uses sound waves to create detailed images of the unborn baby's heart. It can help a health care provider confirm the diagnosis of transposition of the great arteries.
Given the complexity of the abnormality, referral to a multidisciplinary team, including maternal-fetal medicine specialists, pediatric cardiologists, geneticists, and/or neonatologists, is recommended. The purpose is to inform the patient about the suspected diagnosis and prognosis and discuss management options before and after delivery, including the preferred site for delivery.
The fetus tolerates the condition without much difficulty prior to birth; however, approximately one-third of newborns with TGA have extremely low oxygen levels that can harm their bodies and will require urgent intervention. A balloon atrial septostomy (BAS) is expected to take place within hours after birth. This life-saving procedure, which creates or enlarges a hole between the upper chambers of the heart to allow red and blue blood to mix, was developed at Children's Hospital of Philadelphia in the 1960s.
For babies requiring a BAS procedure, the clock begins ticking at the moment of birth, and access to immediate expert care is essential. For this reason, delivery should be planned at a facility with the appropriate level of care and staffing for the mother and baby, including a facility with a level III neonatal intensive care unit (NICU), pediatric cardiology expertise, specialized delivery room care, and cardiac operative and catheterization facilities. If this is not feasible, transport arrangements should be established before delivery.
Children with transposition of the great arteries will require open-heart surgery to treat the defect. Without surgical repair, the overwhelming majority of patients with TGA will not survive their first year. The surgery, known as the arterial switch operation, is typically performed within a few days of birth. Surgeons reconstruct the heart so that the aorta is attached to the left ventricle, and the pulmonary artery is attached to the right ventricle.
The overwhelming majority of children, like Monty, born with TGA, will go on to lead healthy, productive lives. Significant limitations of day-to-day activities, including sports, are uncommon. Carol and Monty's story highlights the importance of selecting medical providers capable and committed to diagnosing and treating our loved ones and us.
 Gerberding, Julie Louise et al. “Improved national prevalence estimates for 18 selected major birth defects--United States, 1999-2001.” MMWR. Morbidity and mortality weekly report 54 51 (2006): 1301-5.
 Ravi P, Mills L, Fruitman D, Savard W, Colen T, Khoo N, Serrano-Lomelin J, Hornberger LK. Population trends in prenatal detection of transposition of great arteries: impact of obstetric screening ultrasound guidelines. Ultrasound Obstet Gynecol. 2018 May;51(5):659-664. doi: 10.1002/uog.17496. PMID: 28436133.
 Bravo-Valenzuela NJ, Peixoto AB, Araujo Júnior E. Prenatal diagnosis of transposition of the great arteries: an updated review. Ultrasonography. 2020;39(4):331-339. doi:10.14366/usg.20055.
 For example, see https://www.chop.edu/centers-programs/fetal-heart-program.
 David R. Fulton, MD, David A. Kane, MD. Management and outcome of D-transposition of the great arteries. UpToDate. Updated Aug. 13, 2021.