Scientists have identified the substance that protects against premature births caused by infection.

Pre-term birth from infection is the leading cause of infant mortality in many countries according to the World Health Organization. The findings by the researchers at UT Southwestern Medical Center are the first to identify the specific role that the substance hyaluronon (HA), plays in the reproductive tract.

Senior author Dr. Mala Mahendroo said that they found that HA, a critical substance made by the body, is required to allow the epithelial lining of the reproductive tract to serve as the first line of defense against bacterial infections. Because of this action, HA offers cervical protection against the bacterial infections that cause 25 to 40 percent of pre-term births in women.

Hyaluronon is a natural substance found in many tissues, and is both a lubricant and a beneficial component of eyes, joints, and skin. It has long been thought to play an essential role in increasing the cervix's flexibility during the birth process; however, the study, which was conducted using mouse models, showed that HA is not essential for increased cervical pliability during late pregnancy. Rather, the substance plays an important barrier role in epithelial cells of the lower reproductive tract and in so doing protects against infection-related pre-term birth. The World Health Organization estimates that 1.09 million children under age 5 die from direct complications of being born prematurely, meaning before the 37th week of pregnancy.

Dr. Yucel Akgul, first author of the study said that the study demonstrates that HA plays a crucial role in the epithelial barrier as well as the cervix's mucus. Next steps include determining the mechanism by which HA affects cervical protection against infection.

The study is published in the Journal of Clinical Investigation.