Generally, ovulation occurs 24-48 hours after intramuscular injection of chorionic villus, and in some cases, ovulation occurs early, about 12 hours after intramuscular injection. After the injection, you should have intercourse on the next day, and then check the ultrasound to see if the follicle is normally ovulated. If the follicle is not ovulated, you can inject half dose of the injection again, and check again the next day to see if the follicle is ovulated. If the follicle has not been ovulated, and the follicle has become luteinized, the diagnosis of Unruptured Follicle Luteinization Syndrome (UFLS) can be made, and the test should be repeated at the time of the menstrual blood test. Generally, the follicle will ovulate normally in a natural cycle, but only in the case of unruptured follicle syndrome or ovulation induction therapy, the follicle may not rupture and an intramuscular injection of chorionic villus is needed.