AZH (Assisted Zona Hatching)

Assisted Zona Hatching (AZH) or Assisted Hatching (AH) - supports the hatching of the embryo out of the zona pellucida, thereby increasing the chances of correct embryo implantation and pregnancy. During an AZH procedure, the embryo's zona pellucida is incised slightly so that the process of hatching (emergence) of the embryo from the zona pellucida is undisturbed.

What is AZH (or AH)?

It is a laboratory technique used in the IVF procedure that involves making a small incision in the embryo's transparent envelope or reducing its thickness with a laser device. AZH assists the process of hatching of the embryo from its casing. Hatching is the physiological process necessary for the embryo to start implanting in the endometrium. During this phenomenon, the growing blastocyst breaks through and escapes from the transparent sheath. Hatching of the embryo must occur before implantation into the endometrium. Hatching of healthy blastocysts in vitro usually occurs between 7 and 8 days after insemination or oocyte microinjection.

When is the AZH procedure used?

Assisted embryo hatching is recommended especially in cases where:

  • couples have a history of at least two unsuccessful IVF treatments,

  • women who are over 38 years of age,

  • the quality of the couple's embryos is described as medium or low,

  • structural abnormalities within the transparent envelope have been identified that may interfere with the embryo hatching process.

 AZH is particularly indicated to increase the success rate of frozen embryo transfer (FET) in cases of preceding implantation failures. 

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