Patent ductus arteriosus symptoms vary with the size of the defect and whether the baby is full term or premature. A small PDA might cause no signs or symptoms and go undetected for some time — even until adulthood. A large PDA can cause signs of heart failure soon after birth.

Your baby's doctor might first suspect a heart defect during a regular checkup after hearing a heart murmur while listening to your baby's heart through a stethoscope.

A large PDA found during infancy or childhood might cause:

• Poor eating, which leads to poor growth
• Sweating with crying or eating
• Persistent fast breathing or breathlessness
• Easy tiring
• Rapid heart rate

Congenital heart defects arise from problems early in the heart's development — but there's often no clear cause. Genetic factors might play a role.

Before birth, a vascular connection (ductus arteriosus) between two major blood vessels leading from the heart — the aorta and pulmonary artery — is necessary for a baby's blood circulation. The ductus arteriosus diverts blood from a baby's lungs while they develop, and the baby receives oxygen from the mother's circulation.

After birth, the ductus arteriosus normally closes within two or three days. In premature infants, the connection often takes longer to close. If the connection remains open, it's referred to as a patent ductus arteriosus.

The abnormal opening causes too much blood to circulate to the baby's lungs and heart. Untreated, the blood pressure in the baby's lungs might increase (pulmonary hypertension) and the baby's heart might enlarge and weaken.

Risk factors for having a patent ductus arteriosus include:

• Premature birth. Patent ductus arteriosus (PDA) occurs more commonly in babies who are born too early than in babies who are born full term.
• Family history and other genetic conditions. A family history of heart defects and other genetic conditions, such as Down syndrome, increase the risk of having a PDA.
• Rubella infection during pregnancy. If you contract German measles (rubella) during pregnancy, your baby's risk of heart defects increases. The rubella virus crosses the placenta and spreads through the baby's circulatory system, damaging blood vessels and organs, including the heart.
• Being born at a high altitude. Babies born above 10,000 feet (3,048 meters) have a greater risk of a PDA than babies born at lower altitudes.
• Being female. PDA is twice as common in girls.

A small patent ductus arteriosus might not cause complications. Larger, untreated defects could cause:

• High blood pressure in the lungs (pulmonary hypertension). Too much blood circulating through the heart's main arteries through a patent ductus arteriosus can lead to pulmonary hypertension, which can cause permanent lung damage. A large patent ductus arteriosus can lead to Eisenmenger syndrome, an irreversible type of pulmonary hypertension.
• Heart failure. A patent ductus arteriosus can eventually cause the heart to enlarge and weaken, leading to heart failure, a chronic condition in which the heart can't pump effectively.
• Heart infection (endocarditis). People who have structural heart problems, such as a patent ductus arteriosus, are at a higher risk of an inflammation of the heart's inner lining (infectious endocarditis) than are people who have healthy hearts.

Patent ductus arteriosus and pregnancy

Most women who have a small patent ductus arteriosus can tolerate pregnancy without problems. However, having a larger defect or complications — such as heart failure, arrhythmias or pulmonary hypertension — can increase the risk of complications during pregnancy. If you have Eisenmenger syndrome, pregnancy should be avoided as it can be life-threatening.

If you have a heart defect, repaired or not, discuss family planning with your doctor. In some cases, preconception consultations with doctors who specialize in congenital cardiology, genetics and high-risk obstetric care are needed. Some heart medications can cause serious problems for a developing baby, and it might be necessary to stop or adjust the medications before you become pregnant.