We did not observe an increased incidence of congenital malformations or fetal aneuploidy in the women who used ART to conceive. A recent study by Zadori et al6 in 2003 reviewed outcomes of 301 neonates born as a result of IVF in a population of more than 12,900 deliveries and found no significant increase in the number of major birth defects. Additionally, in the United States, the Society for Assisted Reproductive Technology reported a prevalence of congenital malformations of 1.9% among patients undergoing IVF, which was similar to that seen in the general population. Retzloff and Hornstein3 in 2003 performed an analysis of 11 major studies from 1996 to 2002 and concluded that the vast majority showed neither an increase in malformations nor clustering of any single specific major malformation in ICSI pregnancies. This finding is complemented by the work done by Bonduelle et al20 in 2002, who studied 2,840 ICSI children and 2,955 IVF children in Brussels. This study found no significant difference in the malformation rate between ICSI and IVF pregnancies. However, our study contradicts the work of Hansen et al7 in 2002, which found an increased incidence of major birth defects in IVF pregnancies with an overall adjusted odds ratio of 2.0. This study found that infants conceived with ART were more likely to have multiple major defects and were also more likely to have chromosomal abnormalities. However, increased diagnostic vigilance of the study population may have resulted in ascertainment bias given the low-risk nature of the control population.21