The criteria for diagnosing pregnancy are a history of menopause, sexual intercourse in women of normal reproductive age, early pregnancy reactions such as morning sickness, vomiting, sweet and sour food, frequent urination and breast tenderness after the postponement of menstruation, and some women may experience fatigue and mental fatigue. The most accurate diagnosis depends on the increase of chorionic gonadotropin level in the blood, as well as gynecological ultrasound, the growth of the gestational sac in the uterine cavity and fetal heartbeat. The simple diagnosis of pregnancy through the darkening of nipples is inaccurate and may lead to misdiagnosis.