Delayed menstruation with lower back pain requires first checking the blood HCG value to rule out pregnancy as the cause. If the blood HCG value rises, it suggests that the patient is pregnant. Further examination of gynecological ultrasound is needed. If the gynecological ultrasound suggests early intrauterine pregnancy and there is no requirement for childbearing, abortion or medication can be performed to terminate the pregnancy; if there is a requirement for childbearing, it is necessary to further combine the progesterone situation and the patient’s clinical symptoms to decide how to deal with the next step. If gynecological ultrasound, intrauterine pregnancy tissue is not found, but a suspicious pregnancy mass is found outside the uterus, it is necessary to combine with the HCG value to further determine whether it is conservative treatment or surgical treatment of ectopic pregnancy. If the HCG value does not rise, in this case, further progesterone withdrawal bleeding treatment is needed, such as dydrogesterone tablets, progesterone injection, etc.. For back pain, further gynecological examination is needed to rule out the presence of pelvic inflammatory disease, if there is pelvic inflammatory disease, oral antibiotic medication, such as metronidazole.