Intrapartum Group B Streptococcus Prophylaxis Not Tied To Childhood Allergic Disorders

Maternal intrapartum group B Streptococcus antibiotic prophylaxis isn't associated with an increased risk for diagnosis of allergic disorders such as asthma, eczema, food allergies, and allergic rhinitis in young children, a new study suggests.

Researchers examined data on 14,046 children who were followed through age 5 years, including 1,919 delivered vaginally and 573 delivered via cesarean section, whose mothers received intravenous penicillin, ampicillin, cefazolin, clindamycin or vancomycin four or more hours before delivery to prevent group B Strep.

There was not a significantly greater risk of the composite primary endpoint of childhood allergic disorders among children delivered vaginally (hazard ratio 1.13) or via cesarean (HR 1.08) who were exposed to prophylactic antibiotics, researchers report in Pediatrics.

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In addition, there was not a significant association between antibiotic prophylaxis and any of the childhood allergic disorders examined independently: asthma, eczema, allergic rhinitis, or food allergy.

"The hypothesis was that we would find an association," said senior study author Dr. Sagori Mukhopadhyay, an assistant professor at the University of Pennsylvania and the Children's Hospital of Philadelphia.

"This was based on the knowledge that intrapartum antibiotic prophylaxis (IAP) administered to laboring women colonized with Group B Streptococcus is reported to alter neonatal microbiome composition and increasing evidence that the early microbiome plays an important role in the child's immune development," Dr. Mukhopadhyay said by email.

As information about the critical role of the microbiome increases, many standard care practices that involve antibiotics will, and should be, viewed newly for unintended consequences, Dr. Mukhopadhyay added.

"Mothers and care providers feel concern for such consequences with antibiotic exposures, especially this early in life, and such concerns when unaddressed can impact compliance," Dr. Mukhopadhyay said. "Our study, we hope, will assuage at least some of these concerns."

One limitation of the study is that medical records used in the analysis might not have identified all cases of childhood allergic disorders, the study team notes. Another limitation is that researchers lacked data on certain potential confounders such as detailed family history of atopic diseases, cigarette smoke exposure, pet exposure, and daycare exposure.

Even so, the results should reassure expectant mothers about taking antibiotics when there is a confirmed bacterial colonization or infection that presents a reasonable risk, said Kelly McNagny, a professor of medical genetics and biomedical engineering at the University of British Columbia in Canada who wasn't involved in the study.

"But don't over prescribe antibiotics prophylactically when there is not a confirmed bacterial colonization/infection that carries a significant risk, particularly in early life," McNagny said by email.

Antibiotics, however are still a routine part of care for some women in labor, and are typically given to all women with cesarean section, regardless of Group B Streptococcal colonization status, said Kirsty Le Doare of St. George's University of London in the U.K.

"There is a lot of anxiety about having antibiotics in labour and the effect this will have on infants in the short and long term," Le Doare, who wasn't involved in the study, said by email. "The fact that this study found no association in a large cohort of children in the USA will be very reassuring to women in countries where antibiotic prophylaxis is a normal part of delivery care."

—Lisa Rapaport

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