Modelling of the probability of success of the stages of in-vitro fertilization and embryo transfer: stimulation, fertilization and implantation.

The aim of this study was to find the factors explaining the probability of success of in-vitro fertilization (IVF)-embryo transfer and its different stages: stimulation, fertilization and implantation. The sample came from a retrospective cohort followed in the IVF-embryo transfer centre of the Centre Hospitalier Universitaire of Pellegrin, Bordeaux, France; the data from 471 couples giving rise to 923 IVF-embryo transfer cycles were recorded. Four logistic regression models were specified for global process, stimulation, fertilization and implantation stages. Random effect models were used for taking into account the correlations of the different cycles for the same woman. The main outcome measures were: ongoing pregnancy, number of oocytes, number of embryos. A total of 135 ongoing pregnancies was observed. The significant explanatory variables were for global process: age [> or = 38 years: odds ratio (OR) = 0.28], donor sperm IVF-embryo transfer (OR = 2.1), number of ampoules (OR = 0.98), previous IVF-embryo transfer livebirth (OR = 2.36); for stimulation: age (> or = 35 years: OR = 0.38) and number of days of treatment > 13 days (OR = 0.20); for fertilization: accident during previous IVF-embryo transfer gestation (OR = 0.39), absolute tubal infertility (OR = 1.38) and the number of ampoules of human menopausal gonadotrophin (HMG) per day (OR = 0.85); for implantation: age (age > or = 38 years: OR = 0.34), donor sperm IVF-embryo transfer (OR = 4.58), number of ampoules (OR = 0.98), number and quality of the embryos. Estimates of the probabilities of success are also given for the global process.