The effect of female age on the likelihood of a live birth from one in-vitro fertilisation treatment.

To determine the chance of at least one live birth from one round of in-vitro fertilisation (IVF) treatment and the effect of the woman's age on that likelihood. Retrospective analysis of outcomes from IVF treatment that did not involve donated gametes, but which included embryos cryopreserved in the retrieval cycle. All IVF patients (median age, 36 years; range, 22-48 years) who attended a private IVF clinic in Sydney for an egg retrieval between 1 January 1998 and 31 December 1998, and had embryo placements (fresh and cryostored) performed up to 30 June 2001. Independently audited live births surviving the neonatal period. 565 women had 648 egg retrievals during the period. The age of peak utilisation of IVF was 39 years. For women aged 34 years or less, the chance of a live birth from one round of egg retrieval and IVF treatment was 52.4% (95% CI, 47%-59%). For women aged 35-44 years, there was a linear decline in the live birth rate, and no babies were born from retrievals at age 45 years and over. There was an age-dependent rise in the frequency of miscarriages, from 10.5% (95% CI, 5%-18%) for women under 35 years, to 16.1% (95% CI, 9%-25%) for those 35-39 years, and 42.9% [95% CI, 24%-63%] for those over 40 years (P < 0.001). A third of the first births resulted from embryo transfers performed after a period of cryostorage. As fertility with IVF falls from the age of 34 years, and the age of peak IVF utilisation is 39 years, many Australian women are seeking IVF at an age when the likelihood of a live birth is reduced.