摘要Background Birth defects constitute a significant public health issue worldwide,yet there is a lack of comprehensive population-based data for the Chinese population.Methods We analyzed data from the China National Population-based Birth Defects Surveillance System from 2007 to 2021,we calculated the prevalence rates of selected birth defects,stratified by maternal residence,geographic region,maternal age,and infant sex.The Joinpoint regression model was utilized to assess trends and annual percent changes in prevalence.Results From 2007 to 2021,significant downward trends in prevalence were observed for neural tube defects(NTDs),hydro-cephalus,cleft lip with or without palate(CL/P),limb reduction defects(LRD),omphalocele,Down syndrome,and tetralogy of Fallot(TOF).Conversely,upward trends were identified for hypospadias,cleft palate(CP),microtia/anotia,polydactyly,syndactyly,ventricular septal defect(VSD),atrial septal defect/patent foramen ovale(ASD/PFO),and patent ductus arte-riosus(PDA).Younger mothers exhibited a higher prevalence of hydrocephalus,gastroschisis,CL/P,and polydactyly,while anotia/microtia,Down syndrome,and congenital heart diseases(CHDs)were more common in mothers aged 35 years or older.Significant variations in the prevalence of anencephalus,spina bifida,CL/P,anorectal atresia/stenosis,hypospadias,polydactyly,syndactyly,VSD,ASD/PFO,and PDA were found across different maternal residences and geographic regions.Conclusion This study highlights the diverse trends and prevalence patterns of major birth defects,underscoring the neces-sity for defect-specific public health interventions.