Additional file 1 Table S1. Search terms. Table S2. Summary of risk of bias assessment using ROBINS-I tool. Fig. S1. Eggers’s test of studies examining the association between opioids exposure and the risk of congenital malformations. Fig. S2. Forest plot of association between opioid exposure and major congenital malformation. Fig. S3. Forest plot of association between opioid exposure and central nervous system malformation. Fig. S4. Forest plot of association between opioid exposure and limb malformation. Fig. S5. Forest plot of assoxiation between opioid exposure and cardiovascular malformation. Fig. S6. Forest plot of association between opioid exposure and gastrointestinal malformation. Fig. S7. Forest plot of association between opioid exposure and ear, face, and neck malformation. Fig. S8. Forest plot of association between opioid exposure and respiratory malformation. Fig. S9. Forest plot of association between opioid exposure and musculoskeletal malformation. Fig. S10. Forest plot of association between opioid exposure and urogenital malformation. Fig. S11. Forest plot of association between opioid exposure and orofacial malformation. Fig. S12. Forest plot of association between opioid exposure and neural tube defects. Fig. S13. Forest plot of association between opioid exposure and gastroschisis. Fig. S14. Forest plot of association between opioid exposure and clubfoot. Fig. S15. Meta-regression according to the year of publication. Fig. S16. Forest plot of subgroup analysis of exposed period. Fig. S17. Forest plot of subgroup analysis of indication. Fig. S18: Forest plot of subgroup analysis of adjusted for confounders. Fig. S19. Forest plot of subgroup analysis of risk of bias assessment