These results indicate that among the entire cohort of children conceived from ART and among the children conceived from FET, the risk for birth defects after ICSI is similar to that after IVF.Abbreviations: IVF: in vitro fertilization; ICSI: intracytoplasmic sperm injection; FET: frozen embryo transfer; ART: assisted reproductive technology; ET: embryo transfer; BMI: body mass index; OHSS: ovarian hyperstimulation syndrome; CMOH: Chinese Ministry of Health; ICD-10: International Classification of Diseases, 10<sup>th</sup> edition; PTB: preterm birth; OR: odds ratio; aOR: adjusted odds ratio; CI: confidence interval.
No significant association was observed between the number of oocytes retrieved (continuous variable) and PTB (adjusted odds ratio [AOR] 1.002, 95% CI 0.994-1.011), very PTB (AOR 1.013, 95% CI 0.994-1.032), SGA (AOR 0.998, 95% CI 0.988-1.009), peri/neonatal death (AOR 1.008, 95% CI 0.975-1.043) or major birth defects (AOR 1.009, 95% CI 0.998-1.020).