What is the definition of infertility in adults according to common clinical guidelines?

• A. Inability to achieve a clinical pregnancy after 12 months of regular, unprotected intercourse (or 6 months if age >35), excluding other known causes.
• B. Inability to conceive after 24 months of trying.
• C. Failure to ovulate in a given menstrual cycle.
• D. A male factor infertility must be present.

Answer: (A)

Infertility is defined by the inability to achieve a clinical pregnancy after a year of regular, unprotected intercourse, or after six months if the person is over 35, assuming no other known causes of infertility are identified. This means the couple has tried consistently without using contraception, and a pregnancy has not been confirmed clinically (typically by ultrasound or a positive pregnancy test). The age-based adjustment exists because fertility declines with age, so in people over 35, it’s reasonable to evaluate sooner.

This definition focuses on the outcome of attempting to conceive to the point of clinical pregnancy, not just a momentary failure to conceive. It also does not require a male factor to be present; infertility can arise from female factors, male factors, both, or unexplained causes, which is why a broad evaluation is appropriate. The other timeframes or conditions described in the alternatives don’t align with how major guidelines define infertility, and anovulation is a specific cause rather than the overall definition of infertility.