PURPOSE OF THE STUDY.
This study was designed to investigate the cesarean mode of delivery as a possible risk factor for the development of several chronic immune disorders.
All full-term children born between January 1973 through January 1, 2012, were identified through the Danish Medical Birth Registry. Two and a half million children were born in the selected period (1973–2012), and after excluding preterm births, still-births, births to mothers born before 1952, and individuals with missing data, 1.9 million children were included in the analysis.
The authors compared cesarean versus vaginal delivery and the incidence of selected immune-mediated diseases: asthma, systemic connective tissue disorders, juvenile arthritis, inflammatory bowel disease (IBD), diabetes type 1, immunodeficiencies, celiac disease, leukemia, and psoriasis. Forearm or elbow fractures were used as negative control conditions. Confounding variables were chosen a priori as gender, parity, birth weight, attained age, calendar time (3-year groups), season of birth, maternal age, and maternal illness (eg, maternal diagnosis of the disease in question).
Of the 1.9 million children evaluated, ∼14% were born via cesarean delivery. In mothers with a diagnosis of type 1 diabetes, cesarean delivery was higher (27%) compared with mothers without the diagnosis. In general, maternal illness was associated with higher rates of cesarean deliveries. There was higher incidence of children diagnosed with asthma (this association remained significant when only children diagnosed with asthma after 5 years of age were taken into account), systemic connective tissue disorders, juvenile arthritis, IBD, immunodeficiencies, and leukemia. No association was found with celiac disease, type 1 diabetes, and psoriasis. There was no association of mode of delivery with arm fracture.
The authors conclude that cesarean delivery appears to provide a shared risk factor for these diseases associated with the immune system. The authors outline several differences between cesarean versus vaginal delivery that could be hypothesized as potential explanations of the differences observed: (1) use of anesthetic agents, (2) use of antibiotics, (3) exposure to a different microbiome in an operating room and not passing through the vaginal canal, and (4) pregnancy factors leading to the need for a cesarean delivery.
This is a significant study because it is the first to investigate the association between the cesarean mode of delivery and the risk of developing a variety of chronic immunologic disorders in a large cohort. The results are consistent with prior studies associating cesarean delivery with increased risk for asthma, IBD and leukemia. The authors did not find an association with celiac disease or diabetes type 1 as others have described, which could be due to differences in methodology or individual differences in the cohort’s genetic and/or environmental background. This study underscores the importance of perinatal events in the mother and child that may impact the development of the immune system. Research into which factors most impact this period could increase our understanding of the etiology of these immune-mediated disorders, and lead to possible therapeutic interventions to prevent their development.
- Copyright © 2015 by the American Academy of Pediatrics