When the amount of fluid in the uterus is small, it can be observed temporarily, but when the amount is large, medication should be given to protect the fetus as prescribed by the doctor. In vitro fertilization-embryo transfer (IVF-ET) is an artificial assisted reproduction technique, which needs to be operated by a professional physician. Generally, after the embryo transfer, luteal support treatment should be continued as prescribed by the doctor. Most of the ultrasound examination is done around 4 weeks after the embryo transfer to clarify the pregnancy, but when the ultrasound suggests that there is a small amount of fluid in the uterine cavity, but the embryo is well-developed and there are no uncomfortable symptoms, it can be temporarily observed and reviewed. However, when the ultrasound suggests a large amount of fluid in the uterine cavity, it may increase the risk of implantation failure, preterm miscarriage, etc. It is necessary to combine the progesterone and blood hCG (human chorionic gonadotropin) test, etc. to carry out the treatment of fertility preservation, pay attention to rest as instructed by the doctor, and give the medication to increase progesterone and gonadotropins to protect the fetus. When there is fluid in the uterus after IVF transplantation, it needs to be actively treated under the guidance of the doctor.