Cesarean birth associated with increased risk for atopic dermatitis in offspring

Cesarean birth increased risk for atopic dermatitis by age 3 years, especially among infants with eczema, according to a presentation at the European Academy of Allergy and Clinical Immunology Hybrid Congress.

“Delivery by cesarean section has been associated with development of allergic disease in the offspring,” Sveinung Torsteinsen Hoel, a medical student at University of Oslo in Norway, said during the presentation.

“However, in studies on cesarean section and its impact on the development of atopic dermatitis, results have been a lot more divergent,” Hoel said.

The Preventing Atopic Dermatitis and Allergies, or PreventADALL, randomized controlled study comprised 2,129 mother-child pairs in Norway and Sweden recruited antenatally.

The cohort included 1,127 boys (52.9%). Gestational age at birth was 40 weeks (standard deviation [SD], 1.34) and birth weight was 3.58 kg (SD, 0.47). Also, 386 of the mothers and 204 of the fathers reported AD.

Children were delivered vaginally, either traditionally (81.3%) or with water birth (4%), or via cesarean section (14.7%), including elective (6.3%) and acute (8.5%) procedures.

Providers diagnosed AD at 3, 6, 12, 24, and/or 36 months using the UK Working Party and/or the Hanifin and Rajka diagnostic criteria. However, Hoel noted, the researchers did not study the skin microbiome of these children.

According to the researchers, 531 (24.9%) of the children had AD by age 3 years. Early-onset AD, defined as eczema at age 3 months with an AD diagnosis by age 3 years, affected 156 (7.3%) of the children. Persistent AD, defined as eczema during the first year of life and at age 3 years with an AD diagnosis by age 3 years, affected 153 (7.2%) of the children.

Cesarean birth overall was associated with an increased risk for AD by age 3 years (adjusted OR [aOR] = 1.33; 95% CI, 1.02-1.74) and for early-onset AD (aOR = 1.63; 95% CI, 1.06-2.48) compared with vaginal delivery.

“This result was independent of parental atopic dermatitis and of the FLG mutation status of the child,” Hoel said.

Infants born via acute cesarean delivery had the highest risk for early-onset AD (aOR = 1.83; 95% CI, 1.09-3.07). However, there was no significant association between birth mode and persistent AD.

“This might suggest that there are other factors than the lack of exposure to maternal vaginal microbiota that mediates this association between cesarean section and atopic dermatitis,” Hoel said.

“The association between cesarean section and cesarean section after start of birth and early-onset atopic dermatitis is, to the best of our knowledge, not previously described and could possibly be related to higher maternal stress or maternal risk factors for cesarean section including pregnancy complications,” he continued.