What Causes Respiratory Distress Syndrome?

A lack of surfactant in a premature baby's lungs causes respiratory distress syndrome (RDS). Surfactant is a liquid that a fetus' lungs start making at around 26 to 34 weeks of pregnancy. It coats the insides of the lungs and keeps them open so they can breathe in air after birth. Without surfactant, the lungs collapse when the baby exhales. The baby then has to work hard to breathe.

Other factors that can increase the chances your baby will develop RDS include:

• If you have diabetes mellitus
• Cesarean delivery
• Stress during delivery, especially hemorrhage (a large blood loss)
• Infection

Some infants born at term develop RDS because they have abnormal genes for surfactant.