Cancer incidence in children conceived with assisted reproduction technology

The authors compared records from the register of children born in Britain between 1978 and 1991 after in vitro fertilisation and the National Registry of childhood tumours. The average length of follow-up was 8.6 years. (follow-up incidence to the fifth birthday was almost complete). Of 2,507 liveborn children born between 1978 and 1991 in Britain after the use of assisted reproduction technology, 2 cancers were identified compared with 3.5 cancers expected. This analysis has little statistical power because childhood cancer is a rare disease. A sample size of at least 20,000 children would be required to reach definite conclusions.