systematic review and meta-analysis reports., a
“Antibiotic use during pregnancy is significantly associated with the development of asthma in children. Additionally prenatal antibiotic exposure is also associated with disorders present in the atopic march including atopic sensitization, dermatitis/eczema, food allergy, allergic rhinitis, and wheeze,” lead study author Alissa Cait, PhD, of Malaghan Institute of Medical Research in Wellington, New Zealand, and colleagues write in Allergy.
“Antibiotics account for 80% of prescribed medications during pregnancy, and it is estimated that 20%-25% of pregnant women receive at least one course of an antibiotic during this time period,” they add.
The researchers evaluated prenatal antibiotic exposure and the risk for childhood wheeze or asthma, as well as for diseases associated with the atopic march, by searching standard medical databases for controlled trials in English, German, French, Dutch, or Arabic involving the use of any antibiotic at any time during pregnancy and for atopic disease incidence in children with asthma or wheeze as primary outcome. They excluded reviews, preclinical data, and descriptive studies.
From the 6,060 citations the search returned, 11 prospective and 16 retrospective studies met the authors’ selection criteria. For each study, they evaluated risk of bias using the Newcastle-Ottawa Quality Assessment Scale, and they rated certainty of the evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) protocol.
The studies, published between 2002 and 2020, were conducted in Europe, North America, Asia, and South America. Exposure to antibiotics during the prenatal period was assessed through unsupervised questionnaires, interviews by medical professionals, or extraction from official medical databases.
The results showed that:
- Antibiotic use during pregnancy was linked with increased relative risk of developing wheeze (relative risk, 1.51; 95% confidence interval, 1.17-1.94) or asthma (RR, 1.28; 95% CI, 1.22-1.34) during childhood.
- Antibiotic use during pregnancy also increased a child’s risk for eczema or dermatitis (RR, 1.28; 95% CI, 1.06-1.53) and allergic rhinitis (RR, 1.13; 95% CI, 1.02-1.25).
- Food allergy increased in one study (RR, 1.81; 95% CI, 1.11-2.95).
Quality of studies
“These results have importance for antibiotic stewardship throughout the prenatal period,” the authors write. However, due to issues including high heterogeneity, publication bias, and lack of population numbers in some studies, the overall quality of the evidence presented in the studies was low. Other limitations include mainly White and European study populations, underpowered studies, and study protocol inconsistencies.
“Though there is evidence that antibiotic treatment during pregnancy is a driver of the atopic march, due to a large heterogeneity between studies more research is needed to draw firm conclusions on this matter,” the authors add. “Future studies should employ and report more direct and objective measurement methods rather than self-reported questionnaires.”
Dustin D. Flannery, DO, MSCE, a neonatologist and clinical researcher in perinatal infectious diseases and neonatal antimicrobial resistance and stewardship at Children’s Hospital of Philadelphia, said in an email that the study was well done.
He noted, though, that “although the study reports an association, it cannot prove causation. The relationship between prenatal antibiotics and childhood allergic disorders is likely multifactorial and quite complex.”
He joins the authors in recommending further related research. “Due to the variation in how exposures and outcomes were defined across the studies, more rigorous research will be needed in this area.”
Despite the study’s limitations, “given that some studies have found associations between prenatal antibiotic exposure and childhood atopic and allergic disorders, including asthma, while other studies have not, this systematic review and meta-analysis asks an important question,” Dr. Flannery, who was not involved in the study, said in an interview.
“Investigators found a strong association between prenatal antibiotic exposure and risk of childhood asthma and other disorders,” he said. “This finding supports efforts to safely reduce antibiotic use during pregnancy.”
The study was supported by the Deutsche Forschungsgemeinschaft and by the Konrad Adenauer Foundation. The authors and Dr. Flannery have disclosed no relevant financial relationships.
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