Cephalosporin is an antibiotic that is mainly used to prevent infections, and this drug does not usually affect menstruation. The biggest influence on menstruation is usually endocrine, some environmental and other factors. If the menstruation is delayed, we need to rule out pregnancy first and see if the hormone level in the body is stable. At the same time, if a woman has been under a lot of mental stress and has a hard life and work, it may also lead to irregular menstruation. It is advisable to go for an ultrasound examination, and for delayed menstruation, a blood test for chorionic gonadotropin should be done, and then according to the results of the test, corresponding treatment and observation should be carried out.