['To compare the value of 17 IVF variables, including a new mean score of transferred embryos (MSTE), in predicting pregnancy rate.', 'Retrospective study.', 'Private IVF unit.', 'Women who underwent 10,000 embryo transfers.', 'Duration of infertility, type of infertility, female age, rank of IVF attempt, type of ovarian treatment, progesterone level, sperm count, sperm motility, sperm morphology, number of retrieved oocytes, number of mature oocytes, maturation rate, number of embryos obtained, fertilization rate, number of transferred embryos, cumulative embryo score (CES), mean score of transferred embryos (MSTE), and pregnancy rate.', 'Outcome of IVF-ET was significantly correlated with female age, type of infertility, number of retrieved oocytes, number of mature oocytes, maturation rate, embryos obtained, fertilization rate, transferred embryos, CES, and MSTE. Multivariate analysis demonstrated that MSTE was a better predictor of pregnancy than the number of transferred embryos and female age.'] Is embryo score a better predictor of pregnancy than the number of transferred embryos or female age?