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Assisted Hatching




Oocyte and embryo of human being, as well as any other mammals are covered with protein tunic (pellucid zone) – which is a sort of an analogue of an eggshell. For the implantation into the uterus, the embryo should tear the outside tunic; this process is called hatching.


It’s supposed that problems with hatching to some extent explain why some married coupes don’t get pregnant. Assisted hatching (AH) is a micromanipulation procedure when an aperture is made in the pellucid zone immediately before the transfer of the embryo to the uterus during IVF program to support to its natural hatching and implantation.


In some cases assisted hatching can increase chances for pregnancy among women at senior ages, patients with inexplicable infertility or couples who had several unsuccessful IVF attempts


The scientific literature brings data that the pellucid zone of patients at the senior reproductive age has a high density which makes the embryo hatching difficult. Although the assisted hatching can increase the percent of pregnancy in these cases, there are no literature data that it has advantages for the younger patients in IVF programs. 


In general criteria for the selection of embryos for the assisted hatching depend on several factors. The decision on the issue of conducting assisted hatching is ruled by such criteria as the age of the woman, FSH level in the peripheral blood, the thickness of the pellucid zone, blastomere fragmentation type and percent, as well as the quantity of blastomeres.   


As a rule, the assisted hatching conducted in all cases when there is a high FSH basal level in the peripheral blood of the woman. With rare exclusions the procedure of the assisted hatching is indicated to patients over 38 years. It’s supposed that the pellucid zone whose average thickness is over 18 nm has a high density. It’s obvious that the given indicator depends on the duration of the ovary stimulation and the age of the woman. In case of thick pellucid zone the assisted hatching is also recommended.


Assisted hatching is also recommended in cases when the percent of blastomere fragmentation makes up 10% or more, as well as in cases of fragmentations of blastomeres of III-IV type, in cases ov availability of embryos having less than 6 blastomeres.


Assisted hatching is not recommended in case of embryos of good quality, thinning of the pellucid zone, as well as during the embryo partition, whose blastomeres are in the meiosis interphase.


Based the scientific data it can be mentioned that the cellular multinuceation is considered as cytogenetic pathology except for cases of dual-nucleation in separate blastomeres which are reversible.


Specialist of the VitroMed clinic apply the assisted hatching for embryos of women over 38, for embryos after cryopreservation, for patients with inexplicable infertility and for couples who had more than 3 unsuccessful IVF cycles. However it’s worth mentioning that the pellucid zone is a protective barrier for the embryo and the hatching procedure itself can damage the embryo. Therefore the final decision on applying assisted hatching is applied individually for each patient based on the analysis of the concrete situation.


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