Results
The jecs-an-20180131 dataset contained information about 104,065 fetuses and 98,255 live singleton births. After applying the study’s inclusion criteria, 74,639 subjects were eligible to participate in this study (Fig. 1). Of the 74,639 mothers, 13,756 (18.4%) and 60,883 (81.6%) underwent cesarean and vaginal delivery, respectively. Of the 13,756 cesarean deliveries, 8,057 (10.8%) and 5,699 (7.6%) were elective and emergency cesarean deliveries, respectively. Table 1 presents the participants’ characteristics. A higher incidence of cesarean delivery was associated with a maternal age at pregnancy ≥ 30 years, parity ≥ 2, GA < 39 weeks, SGA, maternal smoking during pregnancy, higher maternal education, higher annual family income, and pet ownership. A lower incidence of cesarean delivery was associated with primipara and breastfeeding at six months. The rates of asthma, atopic dermatitis, wheezing, and eczema in those born via cesarean delivery were 2.7%, 4.2%, 20.2%, and 18.1%, respectively; while the rates for those born via vaginal delivery were 2.5%, 4.4%, 19.5%, and 19.0%, respectively. There were differences noted in the rate of eczema between the cesarean and vaginal delivery groups, while there were no differences in the rates of asthma, atopic dermatitis, and wheezing.
Multiple logistic regression was performed to assess the risks of asthma, atopic dermatitis, wheezing, and eczema associated with cesarean delivery (Table 2). After adjusting for perinatal and socioeconomic confounding factors, cesarean delivery was not associated with an increased risk of asthma [adjusted ORs (aOR) = 0.97; 95% CI, 0.85–1.10], atopic dermatitis (aOR = 1.02; 95% CI, 0.92–1.13), wheezing (aOR = 0.99; 95% CI, 0.94–1.04), or eczema (aOR = 0.99; 95% CI, 0.94–1.04). After adjusting for perinatal, socioeconomic, and postnatal confounding factors, cesarean delivery was not associated with an increased risk of asthma (aOR = 0.95; 95% CI, 0.84–1.08), atopic dermatitis (aOR = 1.02; 95% CI, 0.92–1.13), wheezing (aOR = 0.98; 95% CI, 0.94–1.04), or eczema (aOR = 0.99; 95% CI, 0.94–1.05). Overall crude ORs and aORs for the association between elective and emergency cesarean delivery (vs. vaginal delivery) and the risks of asthma, atopic dermatitis, wheezing, and eczema are shown in Table 3. After adjusting for perinatal and socioeconomic confounding factors, elective cesarean delivery was associated with an increased risk of wheezing (aOR = 1.07; 95% CI, 1.01–1.13) and emergency cesarean delivery was associated with a decreased risk of eczema (aOR = 0.90; 95% CI, 0.84–0.97). After adjusting for perinatal, socioeconomic, and postnatal confounding factors, emergency cesarean delivery was associated with a decreased risk of eczema (aOR = 0.91; 95% CI, 0.84–0.97).