"More than three quarters of premature babies could be saved with cost-effective interventions such as antenatal corticosteroids," say the researchers.
Antenatal corticosteroids are known to significantly reduce the risk of death, respiratory distress syndrome, cerebroventricular hemorrhage, cerebral palsy and poor motor skills prior to preterm birth.
Worldwide, more than 1 in 10 babies are born prematurely every year, with around 1 million dying each year due to the complications associated with preterm birth. Children surviving preterm birth may have a lifetime of learning disabilities and visual and hearing problems.
In the new study, World Health Organization (WHO) researchers compared the use of antenatal corticosteroids and tocolytic drugs to delay delivery among 303,842 births taking place in 359 hospitals across 29 countries.
"Giving antenatal corticosteroids to women at risk of preterm birth is one of the most effective treatments for reducing newborn death and illness," says study leader Dr. Joshua Vogel from the Department of Reproductive Health and Research at WHO in Geneva, Switzerland.
"More than three quarters of premature babies could be saved with cost-effective interventions such as antenatal corticosteroids," he adds. "This is particularly important in Africa and Asia where more than 60% of preterm deliveries occur and where resources are scarce and it is difficult to provide expensive neonatal care."
The study found that 19% of the women who used antenatal corticosteroids gave birth during the 22-25 week period of their pregnancy, and 24% of women using corticosteroids delivered at 34-36 weeks. However, the researchers say that the benefit of using corticosteroids during these periods of pregnancy "is controversial."
The women most likely to benefit from the treatment are those who gave birth between weeks 26 and 34 of gestation, but the study found that only 52% of these women received corticosteroids.
Almost half of the women in the study with uncomplicated, spontaneous preterm labor who were eligible for tocolytic drugs did not receive them. More than a third of this group received ineffective treatments - bed rest, hydration or magnesium sulfate. Beta-agonists were also commonly used - drugs that expose women and their babies to unnecessary risk.
Only 18% of women eligible for tocolytic drugs and corticosteroids received both treatments, and 42% received neither treatment.
Antenatal corticosteroids are not 'panacea for preterm mortality'
The study finds that use of corticosteroids also varied from country to country. While 91% of eligible women in Jordan and 88% of eligible women in the Occupied Palestinian territory received antenatal corticosteroids, only 16-20% of women in Afghanistan, the Democratic Republic of Congo, Nepal and Niger who required these drugs received them.
In a linked comment, Stuart Dalziel, Caroline Crowther and Jane Harding, from The University of Auckland in New Zealand, write:
"Antenatal corticosteroids are not the panacea for preterm mortality in low-income and middle-income countries. Rather, the drugs should be included in a set of simple, efficacious measures - family planning, access to antenatal care, antibiotic drugs for premature rupture of membranes, immediate and simple care for all babies, effective neonatal resuscitation, and kangaroo mother care.
Future research should not focus on efficacy but on strategies to reduce barriers for appropriate use of antenatal corticosteroids."
Recently, Medical News Today reported on a new urinary test, developed by researchers at Imperial College London in the UK, that can predict preterm birth and poor fetal growth.