Is there a declining trend in ovarian function among infertility clinic patients?

BACKGROUND There is a growing body of evidence that testicular function has decreased rapidly over the last 50 years. However, much less is known about corresponding trends in ovarian function. Herein, we examine the temporal changes in ovarian function in a large sample of infertile patients from the Czech Republic over a period of 14 years. METHODS In a retrospective study, we analysed a large body of data from women, 20-40 years of age, undergoing IVF/ICSI treatment between 1995 and 2008. We defined ovarian function using five variables: basal FSH level, estradiol (E2) level on the day of HCG administration, dose of gonadotrophins used for ovarian stimulation, number of retrieved oocytes and dose of gonadotrophins per oocyte. Controlling simultaneously for temporal changes in patient age and stimulation protocol, we applied generalized additive models to describe the temporal trends. RESULTS During the study period the mean age of the study population increased by 2.7 years. Whereas the basal FSH and gonadotrophin dose did not change over time, the E2 level and oocyte retrieval declined, and the dose of FSH per oocyte increased during the study period. CONCLUSIONS The results are indicative of a small, but detectable decrease in ovarian function over a period of 14 years, which is not causally related to the ageing population.