The follicles change after ovulation, the follicular wall collapses to form many folds, the follicular fluid flows out, the follicular granulosa cells of the follicular wall and the follicular lining cells invade inward and are surrounded by connective tissue of the follicular epithelium together forming the corpus luteum, the follicles do not become smaller after ovulation but are transformed into corpus luteum. If there is no conception, the corpus luteum is clearly different from the diminished follicle on ultrasound, and there are also individual follicles with abnormal development and shrunken and smaller follicles, but they do not become smaller after ovulation, but are transformed into corpus luteum without pregnancy. If the follicle development is abnormal, further endocrine tests should be performed to understand the function of the ovaries. If you are planning to get pregnant, you should actively have intercourse after ovulation to improve the chances of conception.