Laser Assisted Hatching (LAH)

The shell or protective layer of the embryo is called zona pellucida.

This may become hard due to the laboratory techniques involved in IVF or due to freezing techniques.The assisted hatching procedure involves thinning or making a hole in the zona pellucida to help the hatching process of the embryos. There is some evidence that assisted hatching might improve the implantation rate.


A hole can be made in the zona by a micro-needle or with the use of a chemical called acid Tyrode’s solution or with a laser. Of these, the laser technique is the best as it has a greater degree of control and more precision during the procedure. A laser can be used to create a full thickness breach or thinning of the zona pellucida. Assisted hatching is performed immediately prior to transferring the embryos into the womb.

Effect on treatment outcome

Some studies have reported improvement in the outcome following assisted hatching. However, some clinicians have reported no difference in outcome.

Who will benefit from assisted hatching?

  • Women older than 38 years
  • Women with repeated unsuccessful treatments with IVF
  • Women with high FSH
  • Embryos with a thick zona pellucida
  • Embryos that have been frozen and thawed

Assisted hatching is an adjunct treatment and is not recommended for all patients. Please speak to your consultant about whether it might be beneficial for you.

Please refer to the regulator’s web page regarding treatment “add-ons” for further information: HFEA


Assisted hatching increases the risk of monozygotic twinning.

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