In a normal pinworm infection, the pinworms will only come out once. This is because the male pinworm dies directly after mating with the female inside the body, and will be expelled directly from the body with the feces. Female pinworms develop in the cecum and gradually move down the intestinal tract as they mature. When the intestines and anus are relaxed after a person falls asleep, the pinworms crawl out of the anus and lay eggs around the anus. After laying eggs, most of the females will die, and the eggs will develop into infectious eggs after about 6 hours. The eggs will be repeatedly touched and swallowed into the body, resulting in repeated infections, which is why pinworms don’t heal easily with repeated treatments.