Daijiworld Media Network - Stockholm

Stockholm, Jan 9: Maternal use of antibiotics during pregnancy may increase the risk of newborns developing Group B Streptococcus (GBS) disease, a potentially serious bacterial infection, according to a new international study.

GBS bacteria usually live harmlessly in the gut or genital tract, but in vulnerable individuals — especially newborns, older adults and those with weakened immunity — they can cause severe infections such as sepsis, meningitis and pneumonia.

The study, led by researchers from Sweden’s Karolinska Institutet and the University of Antwerp in Belgium, found that prenatal exposure to antibiotics was associated with a higher risk of neonatal GBS disease within four weeks of delivery. Exposure during the early third trimester showed the strongest link.

“Prenatal antibiotic exposure can raise GBS risk within four weeks postpartum, especially in neonates not covered by risk-based intrapartum prophylaxis, with the early third trimester being a critical window of susceptibility,” the researchers noted in their paper published in the Journal of Infection.

The team analysed national health data covering all singleton live births in Sweden between 2006 and 2016. Of the 1,095,644 liveborn singletons studied, 24.5 per cent were exposed to antibiotics before birth. The incidence of GBS disease was higher among exposed neonates than among those unexposed — 0.86 versus 0.66 per 1,000 live births — particularly in babies without established GBS risk factors.

Researchers said the study is the first to directly examine the relationship between prenatal antibiotic exposure and neonatal GBS disease. The findings align with earlier Nordic studies that reported a 16–34 per cent increased risk of infections in early childhood following antibiotic exposure during pregnancy.

Notably, antibiotics active against GBS given close to delivery — within four weeks — did not offer protection against neonatal GBS disease. The association was observed mainly in pregnancies without clinical GBS risk factors, suggesting that limiting antibiotic use during pregnancy could be especially beneficial for this group.

Calling for further research, the team emphasised the need for greater vigilance in monitoring newborns who fall outside existing GBS prevention guidelines, particularly those exposed to antibiotics in the early third trimester.