Infertility occurs in about 15% of couples. About one third of infertility is due to problems with ovulation or an anatomic abnormality of the fallopian tube or peritoneum, such as scarring, adhesions or endometriosis. Another third is due to a male infertility factor, most commonly insufficient sperm production or abnormal motility or morphology. The remaining third is unexplained. In older women unexplained infertility is probably caused by diminished quality and quantity of oocytes, decreased implantation and spontaneous pregnancy wastage.

Infertility occurs in about 15% of couples. About one-third of cases are due to problems with ovulation or other female factors, another third are due to a male infertility factor, and the remaining third are unexplained. In older women, unexplained infertility is probably caused by diminished quality and quantity of oocytes. The first approach to treatment of female-factor infertility generally is the use of drugs that stimulate oocyte production.