Vulvar swelling in the middle of the night may be caused by trauma, boils, vestibular cysts, and squamous cell carcinoma of the vulva. 1. Trauma: If you ride a bicycle on a bumpy road for a long time during the day, or if you make violent movements during coitus, as well as if the vulva is violently injured, the vulvar tissues may become congested and edematous, and the patient may feel the swelling of the vulva in the middle of the night. 2. Boils: Boils are considered to be caused by pathogens such as Staphylococcus aureus infection and streptococcus infection. If the patient has a boil on the vulva, it may be manifested as localized swelling and pain, so the patient may feel the swelling of the vulva in the middle of the night. 3. Vestibular cysts: Vestibular cysts are considered to be caused by vestibulitis and congenital glandular stenosis. The patient will have discomfort such as swelling and pain in the vulva, so the patient will feel swelling in the vulva in the middle of the night. 4. Others: patients with vulvar squamous cell carcinoma, perineal allergy, vulvar sweat gland tumor and other diseases will also feel vulvar swelling in the middle of the night. It is suggested that patients who feel swelling in the middle of the night need to consult a doctor in time to check the cause of the disease, and the doctor will take appropriate measures according to the condition to treat the disease.