The most common cause of secondary infertility in women is blocked fallopian tubes. In this case, a hysterosalpingography with iodine oil should be performed to understand the patency of the fallopian tubes and the specific location of the blockage, which can guide future treatment. Additionally, if a woman has abnormal vaginal discharge, a routine gynecological examination should be conducted to check for any cervical lesions. A vaginal secretion test should be performed to see if vaginal inflammation is affecting normal pregnancy. Some women experience infertility after having an abortion or induced abortion, and for these women, it's also worth considering whether uterine issues are causing secondary infertility. A hysteroscopy can be done to investigate this. When a woman experiences secondary infertility, her sexual partner or spouse should also be examined to assess sperm quality and any potential obstacles in the sperm delivery pathway.