The first thing to consider in a 22 year old woman experiencing amenorrhea, if she is sexually active, is that it is physiologic amenorrhea caused by pregnancy. So you can do a urine pregnancy test after amenorrhea or just check the ultrasound to see if there is any fetal growth and development in the uterine cavity. If there is no pregnancy, you need to consider that it is caused by ovarian endocrine dysfunction, most commonly polycystic ovary syndrome. In some cases, amenorrhea may be caused by premature ovarian failure due to excessive weight loss, so a hormone test is needed to check the endocrine status of the ovaries. If amenorrhea occurs after an abortion, it may be caused by endometrial adhesions or cervical adhesions. Amenorrhea due to cervical adhesions is often associated with cyclical lower abdominal pain and can be diagnosed directly by ultrasound.