Tranquilizer is also known as estradiol valerate, and it is an estrogenic medication. How long you can take estradiol valerate for transfer is determined by hormone levels and endometrial thickness, which is different for everyone. 1. If the alternative cycle freeze-thawed embryo transfer program is taken, the oral administration of estradiol valerate will usually be started on 2-3 days of menstruation, and blood values and endometrial thickness will be monitored regularly after about 8 days of the medication, and blood will be drawn to check for estrogen, progesterone, and luteinizing hormone in general, and progestin will be used to perform the endometrial transformation after the endometrial thickness of the uterine lining is at least 0.8cm in combination with ultrasound results. If D3 embryos are transferred, the embryo transfer will be carried out after 3 days of medication; if blastocysts are transferred, the embryo transfer will be carried out after 5 days of medication, during which estradiol valerate is used all the time, and after the transfer, estradiol valerate and progesterone should continue to be applied, and the specific time of stopping the medication should be followed by the doctor’s advice. 2. If the transfer is a natural cycle and the dominant follicle can be discharged on its own, generally there is no need to add Estradiol Valerate, but if the endometrium is thin, the doctor will add Estradiol Valerate according to his own clinical experience, and this kind of application will not be used for a long period of time in general. It is important to follow your doctor’s instructions for medication during embryo transfer.