Premature babies are at risk of heart problems. The heart is a complex organ that with even the smallest developments can mean real issues. Below describes the most common conditions of the heart in relation to preterm babies.

Patent Ductus Arteriosus

Premature infants are also at risk for heart problems and the most common heart condition affecting these tiny babies is patent ductus arteriosus (PDA). PDA is a heart problem that occurs soon after birth in some preterm babies, the infant’s ductus arteriosus fails to close after birth, which causes abnormal blood flow between two of the major arteries connected to the heart. PDA can often sort itself out over time and very mild cases may not even require treatment.

Incidence of Patent Ductus Arteriosus

The incidence of PDA in premature infants has ranged from 18% to 77% and generally decreases with increasing birth weight and gestational age. This means preemies born before 28 weeks gestational age are much more likely to develop PDA than a premmie born older than 32 weeks gestation. Up to 30% of low birth weight infants (less than 2,500 grams or 5 ½ pounds) develop a PDA. Females are 2-3 times more likely than males to develop PDA. For infants that are born full term, the incidence is about 1 in 2,000 births.

(Koch et al., 2006; Vanhaesebrouck et al., 2007)

PDA has also been associated with an increased risk of other complications such as intraventricular haemorrhage (IVH), necrotising enterocolitis, and chronic lung disease. PDA may indirectly contribute to factors that affect short- and long-term cognitive and academic abilities. intraventricular haemorrhage (IVH), necrotising enterocolitis, and chronic lung disease PDA may indirectly contribute to factors that affect short- and long-term cognitive and academic abilities.

(Lee et al., 2008)

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Patent Ductus Arteriosus

Patent ductus arteriosus (PDA) is a heart condition that is most common amongst preterm infants. Before birth the ductus arteriosus is the blood vessel that connects the pulmonary artery and the aortic arch, which is important before birth because it allows blood to bypass the lungs while the oxygen for the blood comes from the mother and not from the infant breathing air. During fetal development, this shunt protects the right ventricle from pumping against the high resistance in the lungs, which can lead to right ventricular failure if the ductus arteriosus closes in utero. In babies born full term the normal changes in the baby’s circulation mean the ductus arteriosus usually closes during the first 3 days of life. But for preterm infants it often fails to close. When this happens, the oxygen-rich blood from the aorta can mix with the pulmonary artery and can cause breathing difficulties and can put strain on the heart increasing blood pressure and sometimes heart failure.

(Koch, et al., 2006) (Vanhaesebrouck, et al., 2007)

Low Blood Pressure

Low blood pressure is a common complication in preterm babies that may occur soon after birth. Blood pressure is determined by a number of factors such as the amount of fluid inside the blood vessels, how hard the heart pumps, and the tone of the muscles that surround the arteries. It is difficult for medical providers to say exactly what a “normal” blood pressure is for preemie babies as even healthy preemies will have lower blood pressure than babies born at term. Low blood pressure can sometime be due to infections, loss of fluid, medications, or blood loss.

(Zaichkin, 2009)

Other Facts about Preemies and Heart Problems

• Other cardiovascular disorders ranging from major defects to dysfunctional autoregulation of blood vessels have been reported in the preterm literature.
• Cardiovascular malformations affect approximately 6 to 8 infants in every 1000 births
• Preterm infants have more than twice as many cardiovascular malformations than infants born at term, and
• P 1 in 6 infants with cardiovascular malformations is born preterm.

(Tanner, Sabrine, & Wren, 2005)

Technical Reference List

Bell, E. F., Warburton, D., Stonestreet, B. S., & Oh, W. (1980). Effect of fluid administration on the development of symptomatic patent ductus arteriosus and congestive heart failure in premature infants. N Engl J Med, 302(11), 598-604..
Furzan, J. A., Reisch, J., Tyson, J. E., Laird, P., & Rosenfeld, C. R. (1985). Incidence and risk factors for symptomatic patent ductus arteriosus among inborn very-low-birth-weight infants. Early Hum Dev, 12(1), 39-48.
Gonzalez, A., Sosenko, I. R., Chandar, J., Hummler, H., Claure, N., & Bancalari, E. (1996). Influence of infection on patent ductus arteriosus and chronic lung disease in premature infants weighing 1000 grams or less. J Pediatr, 128(4), 470-478.
Jacob, J., Gluck, L., DiSessa, T., Edwards, D., Kulovich, M., Kurlinski, J., et al. (1980). The contribution of PDA in the neonate with severe RDS. J Pediatr, 96(1), 79-87.
Koch, J., Hensley, G., Roy, L., Brown, S., Ramaciotti, C., & Rosenfeld, C. R. (2006). Prevalence of spontaneous closure of the ductus arteriosus in neonates at a birth weight of 1000 grams or less. Pediatrics, 117(4), 1113-1121.
Lee, G. Y., Sohn, Y. B., Kim, M. J., Jeon, G. W., Shim, J. W., Chang, Y. S., et al. (2008). Outcome following surgical closure of patent ductus arteriosus in very low birth weight infants in neonatal intensive care unit. Yonsei Med J, 49(2), 265-271.
Mouzinho, A. I., Rosenfeld, C. R., & Risser, R. (1991). Symptomatic patent ductus arteriosus in very-low-birth-weight infants: 1987-1989. Early Hum Dev, 27(1-2), 65-77.
Tanner, K., Sabrine, N., & Wren, C. (2005). Cardiovascular malformations among preterm infants. Pediatrics, 116(6), e833-838.
Vanhaesebrouck, S., Zonnenberg, I., Vandervoort, P., Bruneel, E., Van Hoestenberghe, M.-R., & Theyskens, C. (2007). Conservative treatment for patent ductus arteriosus in the preterm. Arch Dis Child Fetal Neonatal Ed, 92(4), F244-247.
Zaichkin, J. (2009). Newborn Intensive Care: what every parent needs to know (3rd ed.). MI: Sheridan Books.