The embryo is surrounded by a protein shell called the zona pellucida. A portion of this shell must dissolve for the embryonic cells to escape or “hatch.” Only after hatching can the embryo then attach, or implant to the lining of the uterus in order to establish a pregnancy. Possible reasons for implantation failure could include the inability of the embryo to hatch out of its shell.
Assisted hatching is a procedure where an artificial opening is made in the zona pellucida of the embryo. The goal of this is to assist the embryo in breaking out of its shell to facilitate implantation to the uterine lining. Assisted hatching has traditionally been performed by acid digestion of the zona pellucida. At Fertility Institute of San Diego, we use the latest cutting-edge laser to provide our patients with what we believe is the fastest, safest and most uniform method of performing assisted hatching. This involves using a laser to make a tiny hole in the zona pellucida and takes only a few seconds per embryo thereby minimizing the time they are out of the incubator. It also does not expose the embryos to the potential deleterious effect of the acid digestion.
Some of the patients who would benefit from assisted hatching include:
Present research suggests that the risks to the embryos are minimal with this method of assisted hatching. There appears to be an increased risk of monozygotic twinning (MZT), where the embryo splits resulting in a set of identical twins.