Children conceived using ICSI do not have an increased risk of delayed mental development at 5 years of age

G. I. Leslie*, F. L. Gibson, C. McMahon, J. Cohen, D. M. Saunders, C. Tennant

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

106 Citations (Scopus)


Background: Concerns about possible adverse outcomes for children conceived using ICSI were highlighted in 1998 when 1-year-old ICSI children were found to be at increased risk (relative risk = 9.2) of delayed mental development compared with children conceived naturally or using IYF. As the findings were biologically plausible, it was considered important to reassess child development when a more accurate measure of long-term cognitive ability could be obtained. Methods: The mental development of 97 ICSI, 80 IVF and 110 naturally conceived (NC) children at 5 years of age was assessed using intelligence quotients (IQ) obtained from the Wechsler Preschool and Primary Scales of Intelligence. Results: The mean full-scale IQ was 110 ± 18 for ICSI, 111 ± 13 for IVF and 114 ± 13 for NC children (P = 0.21, non-significant). ICSI children were not at increased risk for delayed (full-scale IQ <85) cognitive development (ICSI 5.2%, IVF 2.5%, NC 0.9%; P = 0.18, non-significant). The only significant independent predictor of below-average full-scale IQ on multivariate analysis was lower maternal education level. Conclusions: These findings suggest that the genetic influence of parental cognitive ability is more important than the mode of conception in determining the long-term intellectual ability of children conceived using ICSI.

Original languageEnglish
Pages (from-to)2067-2072
Number of pages6
JournalHuman Reproduction
Issue number10
Publication statusPublished - 1 Oct 2003
Externally publishedYes


  • Child development
  • Conception model
  • ICSI
  • Intelligence quotient
  • IVF


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