Laser-Assisted Hatching in IVF: Indications, Technique and What the Evidence Says

Laser-assisted hatching (LAH) is one of the most widely offered laboratory procedures in IVF, and also one of the most debated. For embryologists learning micromanipulation, it is important to understand both how to perform it safely and what the evidence actually shows.

Key takeaways

• Laser-assisted hatching thins or opens the zona pellucida using a 1.48 µm diode laser.
• Current evidence does not show a reliable improvement in live birth rates with routine assisted hatching, and ESHRE does not recommend it as a routine add-on.
• Patients should receive balanced information and give informed consent for any add-on procedure.
• Laser skills remain essential for trophectoderm biopsy and for collapsing blastocysts before vitrification.

What assisted hatching is

Before implantation, the embryo must hatch out of its protective shell, the zona pellucida. Assisted hatching thins or opens the zona in the laboratory, on the assumption that this helps embryos that might otherwise struggle to hatch, for example after freezing or in older patients.

How laser-assisted hatching is performed

Most laboratories now use a 1.48 µm diode laser mounted on the inverted microscope. The general steps are:

1. The embryo is held with a holding pipette or positioned in a drop.
2. A target area of the zona is chosen, away from the cells (blastomeres or inner cell mass).
3. The laser is fired in short pulses to either thin the zona or create a small opening.
4. The embryo is rinsed and returned to culture or prepared for transfer.

Safety points:

• Calibrate the laser target regularly
• Use the lowest pulse duration that achieves the effect
• Keep the laser well away from cells to avoid heat damage
• Record the procedure in the embryo's laboratory record

What the evidence says

Assisted hatching has been studied for decades, and the results are not as encouraging as its popularity suggests:

• Systematic reviews have not shown a clear improvement in live birth rates with routine assisted hatching.
• ESHRE's good practice recommendations on IVF add-ons do not recommend assisted hatching for routine use.

This means LAH should not be offered to every patient or marketed as a way to improve success. Patients should receive balanced information, and any use outside clear indications should be part of an honest discussion or a research setting.

Where laser skills do matter

Even though routine hatching is not recommended, laser micromanipulation is an essential skill because it is used in:

• Trophectoderm biopsy for preimplantation genetic testing, where the zona is opened and a few cells are removed
• Collapsing expanded blastocysts before vitrification, which may improve survival after warming
• Other micromanipulation procedures where precise, controlled zona opening is needed

Ethics and regulation

Under the ART (Regulation) Act 2021, procedures must be explained to patients and performed with informed consent. Offering add-ons without clear evidence raises both ethical and consumer-protection concerns, so clinics should document the indication and the information given.

Frequently asked questions

Does laser-assisted hatching increase pregnancy rates?

Current evidence does not show a reliable improvement in live birth rates when it is used routinely.

Is laser hatching safe for the embryo?

When performed correctly, with calibrated equipment and the laser kept away from the cells, it is considered low risk, but heat damage is possible with poor technique.

Why learn LAH if it is not recommended routinely?

Because the same laser skills are needed for embryo biopsy and blastocyst collapse, which are routine tasks in many laboratories.

Learn laser micromanipulation at ReproNest

ReproNest's Advanced ICSI & Micromanipulation Course includes laser handling, zona opening and biopsy preparation on training material, alongside ICSI technique. Read about what ICSI training should cover, or contact us.

This article is educational content for healthcare professionals and trainees. It is not medical advice and does not replace clinical judgement, current guidelines or the ART (Regulation) Act 2021 and Rules 2022.