Infertility is commonly defined as the inability to achieve a pregnancy within 12 months of unprotected intercourse. Approximately 80% to 85% of couples who are trying to become pregnant will successfully conceive within a year. However, certain patients may have recognized factors that preclude normal conception. For them, the 12-month period of waiting makes little sense. Common examples of women with such problems include those who have extremely irregular periods, a history of severe endometriosis, a history of previous tubal pregnancies, or other anatomical factors that would clearly lead to diminished fertility. Since fertility declines significantly as a woman ages, couples are encouraged to seek evaluation for infertility after 6 months of no contraception if the woman is older than age 35.

Another problem related to reproduction is recurrent pregnancy loss. Many women can readily conceive, only to suffer repeated pregnancy losses. These women represent a special subset of those who are unable to successfully reproduce and should be evaluated by a medical professional.