Abdominal swelling in the morning may be caused by pelvic inflammatory disease, pelvic tumor and organic diseases of the digestive system. 1. Pelvic inflammatory disease: Pelvic inflammatory disease is mostly caused by infections in the reproductive tract, which is commonly seen in sexually active women, and the clinical symptoms include abdominal distension, abdominal pain, and increase in vaginal secretion, etc. Pelvic tumor: Tumor may compress the pelvic bladder and organs, which may cause the abdominal distension. 2. Pelvic tumor: the tumor may press the bladder and organs in the pelvis, which may cause abdominal distension, accompanied by frequent urination and lower abdominal pain. 3. Organic diseases of the digestive system: the most common as colitis, colon tumors and other diseases, will be repeated stimulation of the intestinal tract, which will appear in the morning abdominal swelling feeling. It is recommended to go to the hospital for examination, the doctor will give the corresponding diagnosis according to the clinical symptoms, and clarify the cause of the disease in time for targeted treatment.