The relevance of age in female human reproduction – Current situation in Switzerland and pathophysiological background from a comparative perspective

Abstract

During recent years women tend to postpone childbirth to ages when fertility declines. Consequently, an increasing number of women experiences reproductive difficulties and seeks help by assisted reproductive techniques (ART). To investigate the dynamics of age-related fertility in Switzerland we evaluated data from the nationwide FIVNAT-CH statistics on ART as well as from a subsample receiving ART at the Division of Reproductive Endocrinology, University Hospital Zurich.
Since 2000 the average age of women receiving ART increased from 34.9 to 36.3 years in Switzerland and since 2006 numbers of annual ART cycles augmented steadily. The percentage of women ⩾40 increased from 17.2% in 2007 to 19.6% in 2011. In the Zurich cohort AMH, the number of oocytes retrieved, the number of fertilized oocytes with two pronuclei, the number of embryos with an adequate cell number, clinical pregnancy rates as well as life birth/ongoing pregnancy rates were lower in the age group ⩾40 years, especially when compared to 33 year-old women. In the nationwide sample pregnancy rates decreased from about 45% at the age of 30 to less than 3% at the age of 45; delivery rates declined from about 38% to nearly 0%. In the Zurich cohort percentages of clinical pregnancies declined from 46% in women ⩽34 years to 21% in women ⩾40 years. In the national sample as well as in the Zurich cohort the percentage of miscarriages increased dramatically from 15.4% and 22% in women ⩽34 years to 38.6% and 33% in women ⩾40 years, respectively.
Even in a country with high health standards such as Switzerland fertility is declining with age and ART does not succeed to improve reduced fertility. Rodent and primate models enrich our knowledge on the pathophysiological mechanisms underlying reproductive senescence. As non-infertility specialist physicians as well as the general public are not sufficiently aware of the dramatic reduction of chances for life births in women ⩾40 years, medical counseling as well as schools and media should support the distribution of information future parents need for successful family planning.