Intrauterine bacterial growth at birth and risk of asthma and allergic sensitization among offspring at the age of 15 to 17 years

Meta-analysis of antenatal infection and risk of asthma and eczema

“…Half of the studies (n = 5) reported a positive association between maternal infection during pregnancy and asthma in offspring, [1,14,17–19] while the remaining 5 studies did not show a significant association. Five studies [2,15,17–19] were from Europe, 4 [1,12,13,16] from America, and 1 [14] from Australia. Nine studies [1,2,12–15,17–19] adjusted for or matched cases with potential confounding factors such as maternal age at delivery, maternal history of allergic disorders, maternal smoking during pregnancy, birth weight, gestational age, child's age, child's sex.…”

“…Five studies [2,12,13,15,17] used questionnaires (of which 3 studies [13,15,17] specified “report of physician-diagnosed asthma or eczema”), and 5 [1,14,16,18,19] studies diagnosed by physician or medical record review. Participant age range varied between studies, including 2 to 5 years, [14] 15 to 17 years, [15] 3 to 14 years, [2] and 5 to 16 years. [18] Others were at a single time ranging from 1 to 8 years.…”

Changes in Fetal Thymic Immune Cell Populations in a Sheep Model of Intrauterine Inflammation

“…33,34 It is likely that the alterations in the fetal thymus induced by intrauterine inflammation are detrimental, since preterm infants born after exposure to chorioamnionitis appear more susceptible and vulnerable to infection and have an increased risk of sepsis. 13,35 Further, the increased risk of asthma associated with preterm birth as a result of chorioamnionitis 36,37 suggests that effects on immune function have the potential to cause long-term adverse effects. It should be noted that the changes in cell numbers within the thymus that we have observed do not necessarily reflect alterations in function of circulating T cells.…”

Fetal Programming: Early-life Modulations that Affect Adult Outcomes

“…Administration of antibiotics to the mother has been shown to be associated with an increased risk of asthma in the offspring as well as in the number of preterm infants born with chorioamnionitis compared with those born without chorioamnionitis [36,37]. This was confirmed in a cohort study that showed an increase in asthma in children 15-17 years of age who had a intrauterine culture positive for bacteria at cesarean delivery [38]. These findings suggest that environmental exposures and intrauterine microbial growth may increase the risk of asthma development.…”

“…Epigenetic changes (alterations in gene expression that occur in the absence of alterations in DNA sequences), such as DNA methylation, acetylation, histone modifications, changes in microRNA, and chromatin alteration, have been proposed as a mechanism by which fetal programming influences the development of asthmatic phenotype [56•]. These processes have been shown to be Infection/antibiotic exposure [36][37][38] Unwed mother [10] Maternal history of asthma [13] Prematurity [7] Low socioeconomic status [10] Black race [10] Fetal size [14,15,19] Male offspring [10] Smoking in pregnancy [10] Maternal inheritance of polymorphisms [12] Operative delivery [10] Vitamin E intake [39,40] Polycyclic aromatic hydrocarbons [35•] involved in T-cell-major effectors of immune responsedifferentiation [57]. A study published in 2009 in PLoS ONE examined the relationship of DNA methylation of ACSL3 to prenatal exposure to airborne traffic-related PAHs and the development of childhood asthma [35•].…”