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Perinatal changes in size of the fetal great arteries
Hae Soon Kim1, Young Mi Hong, Sejung Sohn
1Department of Pediatrics, Ewha Womans University School of Medicine, Seoul, Korea.
Insights
Fetal circulation undergoes significant changes at birth. The aorta (Ao) increases in size while the pulmonary artery (PA) decreases, equalizing great artery dimensions regardless of birth weight.
Area of Science:
- Cardiovascular Physiology
- Neonatal Adaptation
- Pediatric Cardiology
Background:
- Fetal circulation requires immediate adaptation to extrauterine life after birth.
- Understanding perinatal changes in great artery size is crucial for neonatal health.
Purpose of the Study:
- To evaluate perinatal changes in the size of the aorta (Ao) and pulmonary artery (PA).
- To investigate factors influencing these circulatory changes at birth.
Main Methods:
- Echocardiography was used to measure aortic and pulmonary artery diameters.
- Measurements were taken in 50 healthy term infants one day before and 4-5 days after birth.
Main Results:
- The aorta (Ao) increased in size (7.4 to 8.4 mm, p<0.01) and the pulmonary artery (PA) decreased (9.5 to 8.7 mm, p<0.01) postnatally.
- The Ao/PA ratio significantly increased from 0.78 to 0.97 (p<0.01).
- Prenatal PA diameter and Ao/PA ratio were key predictors of postnatal size changes.
Conclusions:
- Circulatory changes at birth equalize the sizes of the aorta and pulmonary artery.
- These adjustments occur irrespective of the infant's body weight.
Background And Objectives:
At birth, the fetal circulation must immediately adapt to extrauterine life. Our goal was to evaluate perinatal changes in the size of the aorta (Ao) and pulmonary artery (PA), and to investigate factors influencing these changes.
Subjects And Methods:
Aortic and PA diameters were measured by echocardiography in 50 healthy term babies one day before and 4 to 5 days after birth.
Results:
Compared with prenatal measurements, the Ao increased (from 7.4+/-0.6 mm to 8.4+/-0.6 mm, p<0.01) and the PA decreased (from 9.5+/-0.8 mm to 8.7+/-0.8 mm, p<0.01) in size after birth. The Ao/PA ratio increased from 0.78+/-0.07 before birth to 0.97+/-0.08 after birth (p<0.01), but there was no significant difference in the sum of the diameters of the great arteries between pre- and postnatal measurements. Postnatal increases in aortic size correlated negatively with prenatal aortic diameter (r=-0.37, p<0.05), but was not related to body weight. According to multiple regression analysis, significant variables for predicting perinatal changes in size of the Ao and PA were the prenatal Ao/PA ratio and the prenatal PA diameter, respectively.
Conclusion:
Despite a difference existing in prenatal diameters between Ao and PA, circulatory changes at birth make the great artery sizes equal, and do so regardless of body weight.
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