Delayed menstruation for four days stomach pain may be pregnant, such as preeclampsia or ectopic pregnancy may occur stomach pain, the need for further blood tests blood HCG, progesterone, and gynecological ultrasound, according to the examination to determine how to deal with the next step. It can also be caused by menstrual disorders, such as recent work stress, study stress or mental tension, mood swings, and so on, there may be delayed menstruation. Before menstruation, many women will experience stomach pain, which does not require special treatment and can be observed. Can also be seen in patients with pelvic inflammatory disease, for this case need to do further gynecological ultrasound, gynecological examination for a clear diagnosis, if necessary, you can choose antibiotic drug treatment.