Objective To examine the prevalence and risk factors of birth defects among 0 – 5 years old children living in southern area of Guizhou province and to provide references for taking corresponding interventions.

Methods A total of 49 887 minority rural children aged 0 – 5 years were randomly selected using stratified multistage cluster sampling from Qiannan prefecture in southern Guizhou province and surveyed with a face-to-face interview, physical examination, and laboratory test between January 2017 and October 2018.

Results Totally 941 birth defects cases were diagnosed and the crude and standardized prevalence rate of birth defects were 188.63/10 000 and 188.17/10 000 among children surveyed. Unconditional multivariate logistic regression analysis revealed following risk factors for birth defects in the children: male gender (odds ratio OR = 3.225, 95% confidence interval 95% CI: 1.271 – 4.776), Miao nationality (OR = 3.653, 95% CI: 1.238 – 3.895), Maonan nationality (OR = 4.856, 95% CI: 1.467 – 5.126), with a gestational age < 37 weeks at the delivery (OR = 3.207, 95% CI: 1.108 – 3.783), birth weight < 2 500 grams (OR = 3.803, 95% CI: 1.356 – 4.935), per capita annual household income < 5 000 RMB yuan (OR = 2.935, 95% CI: 1.216 – 4.028), mountainous residential environment (OR = 2.864, 95% CI: 1.012 – 3.846), maternal age < 20 years (OR = 3.274, 95% CI: 1.216 – 4.125), maternal age ≥ 35 years (OR = 4.761, 95% CI: 1.334 – 5.628), maternal education of primary school and below (OR = 3.368, 95% CI: 1.264 – 4.265), exposure to harmful substances during pregnancy (OR = 3.225, 95% CI: 1.138 – 4.009), maternal negative emotion during pregnancy (OR = 2.868, 95% CI: 1.217 – 3.139), family history of birth defect (OR = 2.546, 95% CI: 1.207 – 3.118), maternal history of drug abuse (OR = 3.003, 95% CI: 1.141 – 3.971), maternal medication history (OR = 2.881, 95% CI: 1.214 – 3.597), maternal pregnancy complication history (OR = 2.932, 95% CI: 1.133 – 3.084), and maternal mental disorder history (OR = 3.071, 95% CI: 1.225 – 3.762); the protective factors against birth defects resulted from the analysis were having premarital checkup (OR = 0.412, 95% CI: 0.245 – 0.821), taking pre-pregnancy physical examination (OR = 0.642, 95% CI: 0.452 – 0.879), receiving health care during pregnancy (OR = 0.453, 95% CI: 0.302 – 0.732), and with folic acid supplementation during pregnancy (OR = 0.487, 95% CI: 0.276 – 0.865), respectively.

Conclusion The prevalence of birth defects is high among 0 – 5 years old minority rural children in southern Guizhou province and risk factor-specific interventions on birth defects should be carried out in the region.