Antibiotic Use During Pregnancy May Increase Risk of Bacterial Infection in Newborns: Study

New Delhi: The use of antibiotics during pregnancy may increase the risk of newborns developing Group B Streptococcus (GBS) disease, a common but potentially serious bacterial infection, according to a new study.

GBS bacteria typically reside harmlessly in the gut or genital tract, but they can cause severe infections in vulnerable groups such as newborns, older adults, and individuals with weakened immune systems. In infants, GBS can lead to life-threatening conditions including sepsis, meningitis, and pneumonia.

The study, conducted by an international research team from Sweden’s Karolinska Institutet and the University of Antwerp in Belgium, found that prenatal exposure to antibiotics was linked to a higher risk of neonatal GBS disease within four weeks of birth. Exposure during the early third trimester showed the strongest association.

“Prenatal antibiotic exposure may elevate the risk of GBS disease within four weeks after birth, particularly in newborns who are not covered by risk-based intrapartum antibiotic prophylaxis, with the early third trimester emerging as a critical period of vulnerability,” the researchers noted in their paper published in the Journal of Infection.

The population-based cohort study analysed data from all singleton live births in Sweden between 2006 and 2016, using national health registers. Of the 1,095,644 liveborn singletons included, 24.5 per cent had been exposed to antibiotics before birth.

The incidence of GBS was higher among antibiotic-exposed newborns compared to unexposed infants (0.86 versus 0.66 per 1,000 live births), especially among babies without known GBS risk factors.

Researchers said this is the first study to directly examine the link between prenatal antibiotic exposure and neonatal GBS disease. The findings are consistent with earlier Nordic studies that reported a 16–34 per cent higher risk of infections during early childhood among children exposed to antibiotics in the womb.

Notably, the study found that antibiotics active against GBS, when administered close to delivery (within four weeks), did not provide protection against neonatal GBS disease.

The association between prenatal antibiotic exposure and neonatal GBS appeared to be influenced by the presence of clinical GBS risk factors, with an increased risk observed only in pregnancies without such factors. This suggests that limiting unnecessary antibiotic use during pregnancy may be particularly beneficial for mothers without established GBS risk indicators.

The researchers called for further studies and stressed the importance of close monitoring of newborns who fall outside current GBS prevention guidelines, especially those exposed to antibiotics during the early third trimester.

With inputs from IANS