Frozen Embryos
The nature of in vitro fertilization creates a situation where several embryos are created. To transfer all of these embryos may be unhealthy and very risky for complications in both the mother and babies. To avoid this high risk pregnancy, only one to three embryos are transferred to the woman’s uterus. This leaves viable embryos in the laboratory. These embryos undergo a specialized “freezing” process and these frozen embryos are then stored in the laboratory. The frozen embryos remain in storage until the couple is ready to undergo another embryo transfer. During a frozen embryo transfer cycle, the woman’s uterus is hormonally prepared for implantation. Once the lining of the uterus has developed adequately, the embryos are thawed and then transferred to the woman’s uterus. The woman continues to take these hormones until the placenta takes over the hormone production that is necessary for maintaining the pregnancy. The pregnancy continues to develop just like any other pregnancy.
