A Michigan Medicine study shows that scientists have developed a unique, non-invasive technique for measuring blood flow to newborn children's brains at the bedside. This technique may improve medical diagnosis and treatment in general. A fetus's lungs are filled with fluid as it grows, and the placenta is the baby's only source of oxygen. Through a blood channel known as the ductus arteriosus, this oxygenated blood bypasses the lungs and travels to the rest of the body. Babies breathe through their lungs after birth, and the ductus arteriosus usually closes in a few days. However, the vessel doesn't close for around 65% of pre-term newborns. The disorder known as patent ductus arteriosus, or PDA, causes blood to flow in an irregular direction, placing stress on the heart and lungs and depriving the baby's brain and other organs of oxygen and blood.