Assisted Hatching

Assisted Hatching

Assisted hatching (AH) is a laboratory procedure that involves making a small hole in the outer noncellular coat of the embryo, called the zona pellucida. This small hole is thought to assist poorer-quality embryos that have a lower implantation potential in hatching out of the zona pellucida, a process necessary for implantation and the establishment of pregnancy.

Assisted hatching is used to increase the chance of pregnancy if a patient has multiple failed IVF cycles and for all women who are 38 or older. AH has been shown to increase IVF pregnancy rates in these situations.

Embryo Coculture

The term "culture" in IVF means to grow or incubate cells in a defined nutrient solution. Human oocytes and embryos are cultured in vitro for two to four days during the process of IVF before they are returned to the female partner's uterus for implantation. "Coculture" is the use of feeder cells in an in vitro culture system to assist another cell type in its development. In IVF, various cell types have been used for coculture of human embryos in an attempt to improve embryo quality, implantation and pregnancy rates. Although the results of studies done to date are not entirely conclusive, most studies have shown a beneficial effect of coculture on human embryo development and the establishment of pregnancy.

One concern with these past studies is the use of nonpatient cells for coculture of human embryos. When nonpatient cells are used for coculture there is a possibility of disease transmission to the embryo and female partner from contaminants contained within the feeder cells. Therefore, the ideal type of cell for coculture would be derived from the female partner. The Mayflower Women's Hospital IVF Laboratories have developed a new coculture system which uses the patient's own cumulus cells, which are the cells directly surrounding the oocyte, as feeder cells for their human embryos. Each oocyte contains a large number of cumulus cells. A few cells are removed from several oocytes and processed in the laboratory to establish a layer of feeder cells for the embryos after oocyte fertilization. Removal of these cells from the oocyte does not damage the oocyte, and in fact is standard practice for all patients whose oocytes will be fertilized by the ICSI technique.

Published studies show that coculture is most useful when the female partner is 39 and older (and using her own eggs) and for those who have failed four or more IVF attempts. Coculture may improve the quality of the embryo and thus aid in the establishment of pregnancy following transfer to the uterus.