Abstract
The ductus arteriosus is an important structure in the fetal circulation. It connects
the pulmonary artery to the arch of the aorta distal to the origin of the left subclavian
artery and carries most of the right ventricular output. Patency of the ductus arteriosus
is maintained by factors like prostaglandin E2, nitric oxide and low oxygen tension
of the blood. With the advent of ultrasonography and Spectral Doppler, many cases
of ductal constriction have been reported. It can be idiopathic but is usually secondary
to the use of medication like NSAIDs, isoxsuprine, fluoxetine and also some particular
foods rich in polyphenol like herbal teas, dark chocolate, berries and coffee. Idiopathic
ductal constriction is a rare finding. Ductus arteriosus constriction occurs largely
due to inhibition of the prostaglandin synthetase pathway as the ductus arteriosus
becomes more sensitive to prostaglandin inhibitors in later gestation. It is, therefore,
more commonly seen in the 3rd trimester. Because of fetal hyperdynamic compromise,
it results in tricuspid regurgitation, right ventricular hypertrophy and ultimately
right ventricular failure, hydrops, pulmonary hypertension and even intrauterine fetal
death. We present a series of ductus arteriosus constriction, of which 3 cases were
associated with tricuspid regurgitation, 1 case with right sided dominance of the
heart and 1 case with moderate to severe right ventricular hypertrophy. Mild cases
require close fetal monitoring and severe cases may need urgent delivery. Postnatal
prognosis seems to be good in cases of ductal constriction associated with right heart
abnormalities as right heart abnormalities resolve in a couple of weeks, although
pulmonary hypertension and right ventricular failure are major concerns. Preventive
measures include avoiding the use of NSAIDs and other medications especially in the
3rd trimester and changes in maternal dietary habits.
Keywords
Ductus arteriosus constriction - Ductal constriction - Spectral doppler - NSAIDs -
Polyphenol rich foods - Right ventricular failure
