In a ray of hope for preventing pre-term birth, researchers found that use of a drug in pregnant mice entirely stopped premature birth and reduced infant fatalities.

Pre-term birth (being born at less than 37 weeks’ gestation) is a major cause of death in children under five years of age.

“Our studies give us some encouragement that it may be possible to prevent many pre-term births, by using drugs that target the body’s inflammatory mechanisms, probably in combination with antibiotics as well,” said lead study author Sarah Robertson, Director of the Robinson Research Institute, University of Adelaide in Australia.

The study, published in the journal Scientific Reports, tested a drug known for its abilities to switch off pro-inflammatory pathways.

The main causes of pre-term birth are bacterial infection (in around 50 per cent of cases), physical injury or stress causing placental damage, carrying twins or triplets, or from environmental toxins such as air pollution.

Each of these is associated with what researchers describe as an “inflammatory cascade”, which can activate the mother’s immune response and ultimately lead to spontaneous pre-term birth.

This inflammatory cascade is triggered by an immune receptor known as Toll-Like receptor 4 (TLR4), responding to infection, physical injury or stress.

TLR4 is critical to the body’s immune response but it also produces a number of pro-inflammatory effects that are harmful to pregnancy.

“TLR4 is a trigger of spontaneous pre-term birth,” Robertson said.

“For this reason, we wanted to test a drug known for its ability to block the actions of TLR4, to see if that would also prevent pre-term birth,” Robertson noted.

The drug tested in this study is known as (+)-naloxone.

“We found that by treating pregnant mice with (+)-naloxone, it provided complete protection against pre-term birth triggered by bacteria. It also protected against stillbirth and infant death shortly after birth, and led to a correction in birth weight among infants that would otherwise be born at very low birth weight,” Robertson said.