BACKGROUND: Previous studies inconsistently suggest that assisted reproduction technology (ART) may increase the risk of birth defects in children. METHOD(S): Live birth infants, conceived by in vitro fertilization fresh embryo transfer (IVF), intracytoplasmic sperm injection fresh embryo transfer (ICSI), or frozen-thawed embryo transfer (FET) in Reproductive Center of Tongji Hospital (Wuhan, China) between 1997 and 2008, were followed up at birth and after 3 years. Preterm pregnancy, multiple pregnancy, sex ratio (male/female), congenital malformation were compared. RESULT(S): A total of 4,236 children were born after ART (IVF 2,543, ICSI 908, FET 785). Compared with IVF, the rate of preterm pregnancy and sex ratio in ICSI were lower (p < 0.05); the rate of multiple pregnancy in ICSI and FET were all lower than IVF (p < 0.05). Congenital defects were comparable in all groups at birth. In total, 2,908 children participated in the second follow-up from 34 months to 60 months with an average of 40 months, and the cases of birth defects had doubled (3 years: 5.16%, birth: 2.22%). The birth defect rate in boys conceived through ICSI was significantly higher than the IVF group after 3-year follow-up (ICSI boys: 8.62%, IVF boys: 5.21% [p < 0.05]), even though there was no significant difference at birth. CONCLUSION(S): Compared with IVF, FET may not increase risk of birth defects. Children conceived through ICSI, especially males, had higher rates of congenital malformations that were inapparent at birth. So longitudinal monitoring may provide insights into the risks of ART. Birth Defects Research (Part A) 97:744-749, 2013. 2013. (c) 2013 Wiley Periodicals, Inc.