A drug that reduces inflammation has the potential to prevent pre-term birth before symptoms even have a chance to appear.

Researchers from the University of Adelaide in South Australia have found a drug that blocks certain inflammation pathways prevented early birth entirely in pregnant mice.

Lead researcher Professor Sarah Robertson, the Director of the Robinson Research Institute, said that the drug (+)-naloxone could be used much earlier in a pregnancy than previous treatments, potentially before any symptoms had developed.

"Most people when they think of labour, they just think of contractions and then the baby's born," she said.

"We're targeting steps that happen much higher in that cascade of events, things that are occurring a lot earlier and a lot further upstream in that pathway.

"We'd be looking at which women were at risk in the second trimester of pregnancy and then commencing treatment soon thereafter."

While the trial focused on the use of (+)-naloxone as a drug for long-term use, Robertson said it would also be possible to use a higher dosage to delay a pregnancy in emergencies.

"There's also a second use for women who come into a clinic, if they're in sufficiently early stage labour, this drug will also have value as a kind of treatment.

Pre-term births occur due to inflammation responses in the mother's body, caused by the immune system recognising the fetus as foreign and rejecting the pregnancy.

The drug (+)-naloxone works by blocking a specific immunity receptor known as Toll-Like receptor 4 (TLR4) which, while important to the immune system, causes a range of inflammation issues during pregnancy.

The research, published in the Nature journal Scientific Reports, found a number of other birth issues including stillbirth, infant death and low weight could also be treated using (+)-naloxone.

"Often when we use those terms they sound like they're all different things, but they're actually more related than many people would guess," Robertson said.

"So if you can tackle inflammation and assist the immune system to withstand that stress it has benefits for all of those different problems."

Currently pre-term birth is the major cause of death for children under five, with more than 1.1 million deaths each year. Pre-term births make up 12% of all births globally.

Professor Robertson said that more research is still needed to determine if (+)-naloxone or similar drugs can safely be used for human pregnancies.

"It's still at least five years before anyone would consider testing it with pregnancy in humans.

"All of this relates to being able to develop good diagnostics to give us a good handle on predicting who's at risk early enough to get in there and use these interventions."

The Robinson Research Institute brings together internationally renowned researchers in human reproduction, pregnancy and child health.

Article: Novel Toll-like receptor-4 antagonist (+)-naloxone protects mice from inflammation-induced preterm birth, Peck Yin Chin, Camilla L. Dorian, Mark R. Hutchinson, David M. Olson, Kenner C. Rice, Lachlan M. Moldenhauer & Sarah A. Robertson, Scientific Reports, doi:10.1038/srep36112, published online 7 November 2016.