College of LAS « Illinois

Molecular and Integrative Physiology

Relaxing Labor

New drugs may reduce the pain of delivery and the need for cesarean sections.


For a mother-to-be in her ninth month of pregnancy, labor can't come fast enough, but the onset of labor is unpredictable and the delivery process itself is characteristically long and painful. Researchers in LAS have developed a two-drug procedure designed to not only induce rapid and less painful delivery, but also to reduce the need for cesarean sections, which are currently performed during a quarter of all U.S. childbirths annually.

The secret to the procedure is one drug to induce labor, RU 486, and one hormone to help enable labor, relaxin. When O. David Sherwood, professor of molecular and integrative physiology, and postdoctoral researcher Shuangping Zhao, examined the procedure in rats, delivery was more rapid and there was a higher incidence of healthy offspring than in births without the drugs.

RU 486 has been investigated for the last 10 years as a method for inducing labor at the end of a pregnancy (term pregnancy) with favorable results. Though this drug alone begins the birth process, it does not prepare the mother's cervix for delivery to the extent that the incidence of cesarean sections is reduced. Because no change in the need for cesarean sections does little to improve mothers' experiences in the delivery room, Sherwood and his laboratory focused on inducing the cervix to grow and facilitate more natural deliveries. They looked at relaxin because it naturally softens and widens the cervix. In most mammals, the production of relaxin increases as birth approaches, but for some reason in humans relaxin levels drop during pregnancy and are very low during the third trimester when it is needed the most. The researchers theorized that the administration of the hormone before delivery would cause the cervix to "ripen." The results with the rat births were dramatic, and Sherwood's laboratory has since found that not only does relaxin induce the proliferation of new cells in the cervix, it also slows down the death of the old cells.

If someday approved by the FDA, relaxin could mean less cesarean operations, and less pain during delivery, both of which should appeal to women.

Summer 2004