Infertility, by definition is the failure of couple to conceive in one year of trying regular, unprotected sexual intercourse. According to WHO, between 2 and 10% of couples worldwide are unable to conceive a child and a further of 10-25% experience secondary Infertility i.e. are unable to conceive a second or subsequent child. Among these couples, infertility is exclusively a problem in the female in about 40% of cases, exclusively in the men in about 35-40% of cases. In 10% of cases, both partners have detectable abnormalities. After thorough medical examinations, the causes of infertility remain unexplained in 10-15% of couples.
The fertility potential is maximum around 24 years of age. The fertility potential begins to decline by age 30 and accelerates by age 35 years. With advancing age there is decline in ovarian reserve and quality of oocytes. It is also thought the diminished endometrial receptivity with advancing age may play a role.