Scientists gain new insight on triggers for pre-term birth

Mar 13, 2019, 11:10 AM by Donna Ramirez

Image of Ultrasound

SCIENTISTS HAVE GAINED NEW INSIGHT on a poorly understood key player in the timing of labor and delivery, bringing researchers closer to being able to prevent pre-term births.

According to the World Health Organization, an estimated 15 million infants are born too early each year. Complications from pre-term birth are the leading cause of death among children under five years old and are responsible for about a million deaths each year globally. In the U.S., approximately one out of every 10 infants was born prematurely in 2017.

Dr. Ramkumar Menon, UTMB associate professor in the Department of Obstetrics and Gynecology, said that when a woman is at the end of her pregnancy, the normal childbirth process begins when the fetus releases chemicals signaling that his or her organs have matured enough for delivery. This chemical release shifts the mother’s hormone levels, which increases inflammation in the uterus and begins labor and delivery.

“There’s another component of the biological clock that contributes to the timing of birth—a type of cell-to-cell communication between the maternal and fetal cells called paracrine signaling,” said Menon. “Because little is known about what this type of signaling does during pregnancy, we investigated the role of paracrine signals called exosomes in the timing of labor and delivery.”

The researchers collected blood plasma samples from pregnant mice and isolated the exosomes. Exosomes collected during either early or late pregnancy were injected into a separate group of pregnant mice during the human equivalent of the beginning of the third trimester.

“We showed that injecting a high concentration of late-pregnancy exosomes caused labor-associated changes without the other hormonal and chemical triggers usually involved in this process,” Menon said. “Injections of the early-pregnancy exosomes had no effect. This shows that exosomes play a more important role in labor and delivery that has never been reported before.”

UTMB’s Dr. Samantha Sheller-Miller, the primary author of the study, conducted the animal model experiments that produced the novel nding. Other authors contributing to the study were UTMB’s Dr. Jayshil Trivedi and Dr. Steven Yellon from Loma Linda University.