The document discusses unexplained infertility, providing definitions and discussing prevalence, causes, diagnosis, and treatment options. It notes that unexplained infertility affects 10-20% of couples and can cause psychological distress. Potential causes are discussed but many are uncertain and found in fertile couples. Diagnosis involves ruling out known causes through standard investigations. Treatment aims to increase monthly pregnancy rates and options discussed include expectant management, ovulation induction, IUI, IVF, and alternative therapies like letrozole, with success rates provided for each option.