The anal swelling sensation in mid-pregnancy is mostly caused by the increase of the uterus pressing on the intestines, which can easily cause constipation or hemorrhoids by pressing on the rectum. There is also a situation that can not be ruled out, need to see if there is proctitis or anal sinusitis caused by anal distension, caused by inflammatory infection usually need to pay attention to hygiene, cleaning, diet also need to pay special attention to do not eat spicy, cold food, chili, onion, ginger, garlic after eating a kind of easily aggravated inflammation, infection symptoms.