Tubal factor infertility (Fallopian tubes).
Male factor infertility, if the number or quality of spermatozoid make a natural pregnancy difficult or impossible.
Endometriosis and polycystic ovaries, illnesses involving functional abnormalities which make ovarian stimulation, ovarian quality, fertilisation or embryo implantation difficult.
Infertility due to ovarian factor, predominately in women over 38 years old. It is estimated that a rapid decrease in fertility begins 13 years before the menopause.
Unsuccessful attempts at other assisted reproduction techniques such as artificial insemination.
Unexplained infertility, generally arising from abnormalities at the moment of fertilisation.
Other causes (because a pregnancy has to be concieved quickly, because the spem is “valuable”, etc.).