Infertility is defined as failure to conceive after regular unprotected intercourse for 2 years in the absence of known reproductive pathology. One in six couples experiences difficulty conceiving and may experience considerable psychological distress. NICE states that a woman of reproductive age who has not conceived after 1 year of unprotected vaginal sexual intercourse, in the absence of any known cause of infertility, should be offered further assessment and investigation (along with her partner), with earlier referral to a specialist if the woman is over 36 years of age.