ABSTRACT
Success of in vitro fertilisation (IVF) in this text is defined as the number of live births per treatment cycle commenced. A live birth is the delivery of one or more live babies (twins and triplets are thus counted as one live birth) and who survive at least for one month. A treatment cycle commences with the administration of drugs to stimulate the ovaries and includes those cycles where treatment is cancelled or abandoned before embryo replacement. In discussing success rates it is essential to define the denominator as the rates quoted will be higher if the denominator is the rate per egg recovery or embryo replaced.
