The above question is one that I often get from patients during my clinic, so I’ll discuss it here today. When doing IVF, embryo fresh and frozen embryo transfer, both require progesterone support, and the progesterone used is available in injections and vaginal gel, both of which are currently available in our hospital, and both should be similar in terms of effectiveness. Two progesterone shots is also 40 mg, which is equivalent to the effect of one 90 mg progesterone gel. Progesterone injections, because they are oil, are very difficult to absorb and therefore can cause swelling and pain in the patient’s buttocks and even septicemia after long-term use. The advantage of vaginal medication is that it is convenient and does not need to be used in the hospital, but the patient can use it at home. In addition, if the patient has vaginal bleeding, it is not suitable for use. Many patients know that some time ago, our hospital and many areas in Zhejiang Province have appeared because of the use of progesterone injections in Tianjin, “red buttocks” incident, this incident is mainly because of the possible poor absorption of this drug, but also and progesterone itself absorption difficulties have a lot to do with, because we used to use progesterone injections in the past After using progesterone injections for a long time, there are also many patients who have red buttocks. So basically, in our center now, we use progesterone vaginal gel as a luteal support drug for both fresh and frozen embryo transfer, and this is also the mainstream method of medication in the international arena. However, for patients who have vaginal bleeding, or who experience adverse reactions after using vaginal gel, they can also propose with their doctor to use injections for luteal support.