(315) Group B streptococcus colonization: Is it a risk factor for autism spectrum disorder of offspring?

The mechanisms driving autism spectrum disorder (ASD) development are not clear. Some obstetric conditions such as infections during pregnancy were linked to ASD, perhaps by affecting in-utero brain development. Group B Streptococcus (GBS) is a well-known organism which colonize the genital tract. GBS colonization during pregnancy and near delivery is associated with short-term infant morbidity, sepsis and mortality. Nevertheless, data regarding long-term pediatric effects is scarce.  We aimed to study the association between GBS colonization in pregnancy and the risk of ASD development later in childhood.

Study Design: We performed a population based retrospective cohort analysis, in which ASD morbidity was compared between offspring to mothers with GBS colonization in pregnancy and offspring of mothers with negative or unknown GBS status. All singletons born between the years 2005 and 2021 at a single tertiary medical center were included in the study. Infants with known malformations, multiple gestations, and cesarean deliveries were excluded. Diagnoses were retrieved from a pre-defined set of ICD-9 codes, recorded in community-based clinics and hospitalization records.  Cox proportional hazards model was used to adjust for confounders to assess association between GBS colonization and the risk of ASD. 

Results:

The study population included 146103 singletons. Of them, positive GBS was recorded in 2225 (1.5%) women. Long-term autism rates were comparable between both groups (0.4% vs. 0.5%, OR 0.99, 95% CI 0.53-1.87, p=0.995; Table). The cumulative incidence of long-term autism morbidity was higher in the group of positive GBS status (Figure, Log-rank p=0.03).  However, using a Cox proportional hazards model, controlling for maternal age, offspring gender and ethnicity, no association was noted between GBS colonization and ASD of offspring (Table, Adjusted HR=1.51, 95% CI 0.78-2.93, p=0.218). 

Conclusion: GBS colonization in pregnancy is not independently associated with an increased risk for long-term autism of the offspring.