Breasts are not swollen and painful, the absence of menstrual period may be pregnant, but also endocrine disorders, thyroid function abnormalities and other causes. 1. Pregnancy: If a woman has sex without proper contraception, it is very likely to lead to pregnancy. After pregnancy, there will be symptoms such as menopause, breast swelling and pain, nausea and vomiting. You need to use a pregnancy test to determine. 2. Endocrine disorders: Women who lose weight excessively, changes in the environment, mental stress, often stay up late and other reasons may lead to endocrine disorders, thus affecting the ovarian function leading to delayed menstruation. 3. Abnormal thyroid function: If female friends suffer from hyperthyroidism or hypothyroidism, thyroid tumors can easily affect the function of the thyroid gland, which can lead to menstrual disorders. It is recommended that women who have delayed menstruation should go to the hospital as soon as possible to have a clear diagnosis and cooperate with the doctor to deal with the symptoms.