Ovulation usually occurs within 24 hours after the ovulation injection. The more commonly used clinical ovulation injection is human chorionic gonadotropin HCG, whose main function is to stimulate ovulation, promote the formation of the corpus luteum and maintain the function of the corpus luteum. A typical intramuscular injection of 10,000 units of HCG is equivalent to 20 times the peak luteinizing hormone of the natural ovulatory cycle and can last for many days, helping the development of the corpus luteum. The dominant follicle will rupture within 24 hours after ovulation, and the chance of conception is highest within 12 hours after ovulation, so intercourse can be arranged on the day of ovulation and the next day to increase the success rate of conception. If there is ovulation disorder, ovulation may not occur in time after ovulation promotion. You can combine ultrasound monitoring and hormone level testing to clearly understand whether ovulation is occurring. Abnormal reactions such as ovarian hyperstimulation and poor response can occur after ovulation injections, so the ovulation protocol should be formulated by a professional doctor according to your situation.