Abstract: AbstractObjective: To evaluate the association between the antibiotic use during pregnancy and childhood asthma. Methods: The Chinese and English databases CNKI, Wanfang Data，Chinese VIP science and technology periodical database, PubMed, EMBASE, Cochrane and ovid were searched for cohort studies on the association between the use of antibacterial agents in pregnancy and childhood asthma. This meta-analysis with Stata12.0 software explored the relationship between antibiotic and asthma.Results: There were 9 studies with the prevalence of childhood asthma and asthma exposure results related factors (OR, RR or HR) and were adjusted for maternal asthma, smoking and other confounding factors.The results of the meta-analysis showed that the use of antibacterial agents in pregnancy increased the risk of childhood asthma (OR=1.14, 95%CI: 1.13-1.15).Because of the high heterogeneity(I2=96.5%),analysis of the heterogeneity among literatures was carried out: the sensitivity analysis was made by removing each article,and the pooled risk estimates of asthma (OR=1.27, 95% CI: 1.17-1.38, I2=0）after excluding the studies of high heterogeneity that did not affect the final result;analysis of clinical heterogeneity: the subgroup analysis with the age of 3 years of asthma onset was performed ,and the pooled effect size OR of studies with < 3 years and ≥3 years respectively was 1.85(95%CI: 0.80-4.29, I2=78.8%) and OR=1.19 (95%CI: 1.08-1.31, I2=96.8%); stratified by trimesters of pregnancy, the OR was 1.29(95%CI: 1.23-1.34), 1.30(95%CI: 1.25-1.35) and 1.26(95%CI: 1.21-1.31) for the early-, mid-and late- pregnancy, respectively, and I2 =0; stratified by antibiotic assessment, the pooled OR from self reporting(interviews) and from the database was 1.27 (95%CI: 1.10-1.48, I2=71.2%), and 1.20 (95%CI:1.08-1.32, I2=98.6%) respectively; stratified by antibiotic tepy,the OR was 1.18（95%CI: 1.08-1.30，I2=0） for Beta- lactam antibiotics and 1.19（95%CI: 0.78-1.83，I2=83.5%）for Sulfonamides and trimethoprim. ②In sibling analyses, the pooled OR was 0.91 (95%CI: 0.79-1.06, I2=93.3%). There was no publication bias by the Begg rank correlation test and the Egger linear regression test.Conclusion: This meta-analysis suggested that antibiotic exposure during pregnancy may increase the risk of asthma in offspring.But in the sibling control analysis the associations disappeared, indicating the residual factors such as family environment,heredity and so on were important confounding factors that may lead to reverse causality. Therefore, the causal relationship between antibiotic use during pregnancy and risk of asthma in offspring needs further investigation.