To determine the cause of a woman's fertility challenges, a range of investigations may be necessary. These assessments include various tests aimed at diagnosing female fertility. For example, blood tests for hormone levels such as FSH, LH, prolactin, estradiol, T4, and TSH are typically conducted on day 2, day 3, or day 4 of the menstrual cycle. Additionally, an Anti-Mullerian Hormone (AMH) level is measured on any day of the cycle to assess ovarian reserve. Elevated FSH levels may suggest a reduction in the number of eggs in the ovaries, while increased prolactin levels can inhibit the release of FSH and LH, contributing to infertility. It is also essential to evaluate T4 and TSH levels, as inadequate thyroid function can affect a woman's ability to conceive. These various tests and investigations are vital in identifying the underlying causes of fertility challenges in women and facilitating appropriate treatment.