Hello and Welcome to ‘Ask A Doctor’ service.
I have reviewed your query and here is my advice. Ovulation occurs 38 to 40 hours after a single HCG injection
Once the follicle is ruptured and the egg is released, your doctor will confirm it through ultrasound
and you need to have unprotected sex within 24-36 hours for fertilization to happen so that you can conceive.
Hope I have answered your query. Let me know if I can assist you further.
Dr. Mohammed Tauseef