Cumulative success rates following mild IVF in unselected infertile patients: a 3-year, single-centre cohort study

A 3-year, retrospective, single-centre cohort study was conducted in a private infertility centre to determine the cumulative delivery rates following minimal ovarian stimulation/natural-cycle IVF in unselected infertile patients. A total of 727 consecutive infertile patients were analysed who underwent 2876 treatment cycles (median four) with scheduled oocyte retrieval from November 2008 to December 2011. Natural-cycle IVF or clomiphene-based minimal ovarian stimulation was coupled with a universal single-embryo transfer policy and increased use of delayed cryopreserved blastocyst transfer. Main outcome measures were crude and expected age-specific cumulative delivery rates. Crude cumulative live birth rates were 65%, 60%, 39%, 15% and 5% in patients aged 26-34, 35-37, 38-40, 41-42 and 43-44 years, respectively. No live births occurred in patients aged ⩾45 years. Dropout rates per cycle varied between 13% and 25%. A plateau in success rates was reached gradually with few additional live births after six cycles. Most of the expected success rate was reached within 6 months, with almost maximal rates within 15 months of the first oocyte retrieval. Acceptable cumulative live birth rates are reached with an exclusive minimal ovarian stimulation/single-embryo transfer policy especially in patients aged <38 years.