If after fertilization it was not possible to obtain more embryos than the amount which is necessary for the embryo transfer or if during existing cycle the embryo transfer was not possible, in this case after patient's request it is possible to freeze embryos in a very low temperature and to store in liquid nitrogen. Frozen embryos may be used for another attempt if previous transfer did not have a successful result and/or if the couple wants to have more children in the future. It is possible to store embryos for an unlimited time period. Embryos will be frozen on the day of embryo transfer procedure or if they are 3 day embryos then it is possible to grow them until the stage of the blastocyst and then freeze embryos. When the couple is ready for the baby, the embryos are thawed and can be used for a second attempt at a negative outcome of the ART procedure and / or for the birth of the second and subsequent children in the future. Embryos are thawed on the same day as the embryotransfer occurs and, together with the liquid, are transferred into the uterine cavity by the help of a thin catheter under ultrasound control. This procedure is completely painless and occurs without the use of anesthesia. Sometimes, it is necessary to prepare the endometrium (mucous uterus) with hormonal preparations before this procedure. Ultrasound control (monitoring) is mandatory, but there is no need for repeated stimulation and puncture of the ovaries. Embryos, according to the legislation of the Republic of Latvia, can be stored for 10 years.