In most cases, menstruation is delayed after ovulation because under natural conditions, normal ovulation occurs around the 16th day of menstruation, after which the corpus luteum forms and then slowly shrinks before menstruation occurs, which is about 14 days after ovulation. In this case, ovulation usually occurs on the 18th to 20th day of menstruation, and menstruation is naturally delayed for 3 to 5 days. Therefore, there is no need to be nervous about the delay of menstruation after ovulation promotion, which is mainly caused by the action of drugs.