When a Dog is Born with a Hole by His Heart

A life-threatening congenital defect — but one that can be fixed.


When a developing puppy is growing inside his mother, he does not need to breathe. The oxygen he requires to mature in utero comes not from his lungs but from the umbilical cord. Thus, after coursing through the body, blood does not travel through the fetus’s lungs to pick up oxygen for another pump out to the body by the heart. The lungs remain deflated, and blood bypasses them through a kind of shunt called the ductus arteriosus.

To continue reading this article or issue you must be a paid subscriber. Sign in

Subscribe to Tufts Your Dog

Get the next year of Tufts Your Dog for just $20. And access all of our online content - over 1,000 articles - free of charge.
Subscribe today and save 44%. It's like getting 5 months FREE!
Already Subscribed?
Click Here to Sign In | Forgot your password? | Activate Web Access