The reason why a 40-year-old woman is frigid about sex may be due to sexual aversion, hormone decline, hypothyroidism and other reasons. 1. Sexual aversion: due to psychological factors, a feeling of aversion to sex or sexual contact with a sexual partner is more exclusive. 2. Hormone decline: As women age, estrogen levels will continue to decline, pelvic floor muscle tone decreases, vaginal atrophy and dryness, etc., and there will be pain during sex, all of which will affect sexual desire. 3. Hypothyroidism: endocrine disorders in the patient’s body, so that the body’s thyroid hormone levels decline, thus causing the patient’s low metabolism or thyroid hormone can not play the normal physiological function, will also affect the libido. In addition, it may also be the wrong sexual concepts, lack of sexual knowledge and other reasons, sexual life abnormalities, it is recommended to consult a doctor in a timely manner, follow the doctor’s instructions for further examination, with the help of the doctor to clarify the reasons, and targeted treatment.