The human embryo at early stages of development is surrounded with protective two-layer coating which thickness makes 13-15 microns. After fertilization of ootid the first spermatozoa, and coating promptly thicken, interfering with penetration of other spermatozoa. Besides the coating facilitates carry impregnated ootid on the uterine pipe. When the embryo comes nearer to cavity of the uterus, a coating becomes thinner. This process occurs under action of special hormones. The thin coating is broken off and an embryo released from it. Process of clearing of an embryo from a coating refers to hatching. The embryo released from a coating has more chances to be attached to wall of the uterus and to continue own development.
In 1990, J. Cohen, one of authoritative experts in the field of reproductive technologies, assumed that at the embryos, which received with the help of method IVF, the coating has thicker walls. This fact explained low productivity of implantation is artificially received embryos. Thus, for improvement of process of implantation J. Cohen developed assisted hatching procedure. The essence of assisted hatching procedure consists that a coating of an embryo at the certain stage of its development is artificially collapsed with the help of various manipulations. Results of modern researches have shown that the most effective is partial destruction of embryo's coating. Carrying out of assisted hatching procedure considerably facilitates implantation of an embryo in the uterus.
There are some kinds of assisted hatching procedure: mechanical, chemical and laser hatching. First two kinds of procedure are developed and described by J. Cohen. During these manipulations coating of an embryo is pierced with a micro needle or dissolved in special acid. However, while carrying out of these manipulations there may be damage of an embryo.
Laser assisted hatching procedure was developed in 1991 by Y. Tadir and D.Palankar. The laser beam bored through in the coating of an embryo micro tunnel. However, safety of application of laser beam at carrying out of operations with embryos still is not proven. Therefore the modern technology of laser hatching is constantly being changed. There are techniques of carrying out laser hatching when the coating of embryo is not bored through but cut off.
One of original updating of laser hatching is the method of destruction of embryo's coating by an infra-red beam. This method is considered the safest and perspective method among various assisted hatching procedures.
Assisted hatching procedure is recommended to application in view of medical observation. To such observation concern unsuccessfully repeated operations on IVF, thickening coating of an embryo, use of the frozen embryos. Besides women who are older than 35 years are included in a number of assisted hatching candidates. Under the recommendation of the doctor, patients can be included in a number of assisted hatching candidates with other diagnoses.