Monday, August 4, 2014

Disposition Of Unused Embryos After IVF

By Annabelle Holman


In vitro fertilization is a procedure that childless couples may use when they are having trouble conceiving the natural way. It is the next step after artificial insemination has failed to yield the desired result. The IVF procedure involves fertilization of the woman's eggs in a petri dish and then implanting the resulting embryos. Unused embryos are a byproduct of this process. There are a number of different ways of dealing with these and it is the responsibility of the parents to determine what happens to them.

Once the eggs are fertilized, spare embryos that are not implanted may be frozen and stored. With modern vitrification freezing techniques, these living embryos may remain viable for years. Parents may decide to store them for future use, donate them for pioneering stem cell research, donate them to other couples who are unable to create their own embryos, continue to store them year after year or they may choose to have them destroyed.

Stem cells are very primitive cells that have the potential to differentiate into just about any other cell type in the human body. This property is referred to as pluripotency. These cells are becoming more and more useful in medicine. There is a significant potential for abuse of these cells. For this reason, their use is very closely regulated by governmental authorities.

Scientists at the University of Utah were the first to inject stem cells into the left ventricles of patients to treat heart failure. Cardiac repair cells were drawn from the patients' own bone marrow and placed into culture for around 12 days. The cells that survived in culture turned out to be stronger than the patient's original cells and were injected into the left ventricles of the patients' hearts.

Stem cells were first isolated from mice in 1981 and in humans in 1998. Some are derived from human embryos that were not used in IVF, although there are other sources. Stem cells may also be harvested from umbilical cords, bone marrow and peripheral blood. Stem cells have shown promise in treating many different medical conditions. These include cancer, neurological disorders and diabetes.

Bone marrow is the spongy tissue located deep in the center of some of the larger bones in the body, mostly from the pelvic bone. Harvesting stem cells from this location is extremely painful so the donors are placed under a general anesthetic. A large needle is then placed into the marrow via the hip bone and the cells are harvested.

Peripheral blood is not normally a rich source of stem cells. However, when donors are given hormones called growth factors a few days before the harvest increases their cell numbers. This process can take several hours. The blood of newborn babies is rich in stem cells. Those left in the umbilical cord are harvested and frozen for future transplantation. So far, umbilical cord cell transplants have only been conducted in children and small adults.

When couples who have stored embryos no longer want to have children, they may donate the spare embryos to scientific research or they may give them to other couples who are having trouble conceiving by other means.




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