The antagonist regimen is with gonadotropin-releasing hormone antagonists, and egg retrieval is usually possible when the follicle is 1.4 to 2.2 cm. Normally, the patient is also given an injection of human chorionic gonadotropin, usually 35 to 36 hours before egg retrieval. If the injection is given too early or too late, it may affect the quantity and quality of the eggs retrieved. Therefore, patients treated with antagonist regimen need to monitor the follicle size regularly under the doctor’s guidance, and when the follicle size reaches the standard for egg retrieval, they need to follow the doctor’s instruction and inject the human chorionic gonadotropin within the prescribed time. Due to the different physical conditions of each IVF patient, the specific size of the follicles during egg retrieval also varies, and the specific size of the follicles during egg retrieval, you need to consult your doctor.