Human egg cell and embryo during early stages of development are surrounded by extracellular pellucid zone (Latin. zona pellucida, ZP) consisting of different glycoprotein molecules. This membrane plays an important role at the stage of fertilization: after penetration of the sperm cell into the egg, the membrane changes its structure, not letting the rest of the sperm cells to penetrate it.
Fertilized egg becomes the embryo, which is still protected by the pellucid zone till 5th-7th day of development. By the end of this period, breakage of the membrane and release of the embryo occur. This event in development of the embryo is called “hatching”. Only after its successful completion the embryo is able to contact with the cells of the endometrium and to be implanted. However, not always embryos successfully leave the pellucid zone. This may be due to molecular changes in composition of the egg membrane that is described in scientific literature as “hardening”.
It is mentioned that intense hardening of ZP occurs in the eggs retrieved in females older than 38 years that is, probably, determined by endocrine changes. Cryopreservation of oocytes and embryos also affects glycoproteins of ZP that leads to its hardening. In addition, the embryos obtained through in-vitro fertilization can have decrease in secretion of special enzymes that dissolve the membrane, make it thinner, leading to the exit of the embryo. All this may interfere with the natural course of hatching and thus prevent attachment of the embryo to the wall of the uterine cavity.
For this reason, the procedure of assisted hatching was developed, being aimed at facilitating release of the embryo from the pellucid zone. The essence of this micromanipulation is punching the pellucid of the embryo which can be done in different ways. In Academician V.I. Gryshchenko Clinic for Reproductive Medicine, assisted hatching is made by means of a laser.
Laser assisted hatching is recommended in case of:
• transfer of thawed embryos;
• 2 or more failed attempts at IVF;
• female at the age over 38 years.
Two-day-old human embryos after non-contact laser assisted hatching. There is a visible punched hole on the membrane of the embryos – result of the assisted hatching.
Cost of services "Assisted hatching"
|Вспомогательный хэтчинг (мин./оптим.)||3400/3400 UAH|
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