In 2001, analysis of Swiss data collected since 1993 included 1001 treatment cycles with IVF, 2217 treatment cycles with intracytoplasmic sperm injection and 2160 treatment cycles with frozen-thawed embryos or zygotes. IVF cycle number has remained constant over the past 10 years, now representing only 18% of the total. ICSI treatment cycles have plateaued since 2001. Altogether, patients receive 1.56 treatment cycles per year, nearly constant since 1995. Mean maternal age has increased from 33.9 to 35.7 years, while mean number of recovered oocytes has increased by 1.3. Considerable improvement was seen in clinical pregnancy rate after 'fresh' treatment cycles since 2000. Mean number of replaced embryos in 'fresh' treatment cycles has fallen to below 2.5 since 1996, long before the legal imposition of the three-embryo transfer limit in 2001, and is still decreasing without affecting the consistent twin pregnancy rate of 19%. The frequency of ovarian hyperstimulation syndrome has increased three-fold. External audits have reduced the mean number of errors per data file by half, and increased the number of correct files by 20%. Data collected over this 10-year period show that despite the introduction of a restrictive law and increasing mean maternal age, the overall clinical pregnancy rate has continued to improve.