Assisted hatching is a crucial step in the IVF process that has shown to increase the success rate of pregnancies by facilitating the embryos to stick to the uterine lining, leading to a successful implantation. Assisted hatching is a procedure by which the outer layer or zona pellucida is manually ground to reduce the thickness of the outer layer, pierced or dissolved to allow the embryo to rupture or hatch.
Assisted hatching is of three types. Chemical assisted hatching, is a process by which an acidic solution is released close to the zona pellucida so as to dissolve and digest it. In Manual Assisted hatching, the embryo is held between a special pipette and fine glass needle. The outer layer then is carefully grinded away till it is thin enough to allow the rupturing naturaly. Laser Assisted Hatching involves using lasers to soften the outer layer and thus improve implantation and pregnancy rates using swift non-contact micro-drilling.
Off all the techniques employed for assisted hatching or embryo drilling, Laser Assisted Hatching is relatively safest and most efficient. The technique uses UV laser micro beam to achieve the desired results in a quick fashioned non-contact procedure.
The use of laser in Laser Assisted Hatching procedures allows for a more precise embryo drilling technique. Usually infrared diode lasers of 1.48 micron are used to create a gap in the outer layer.
The laser assisted hatching procedure is quicker than the other assisted hatching techniques. This is advantageous in that the embryos can be returned to their culture conditions quickly, which is conducive to their quality.
In laser assisted hatching, chemicals are not used and neither the embryos are physically handled or rubbed. This significantly reduces and negates the possibility of the embryo damage. The laser beam from an infrared diode is responsible for the reducing the thickness of the outer later or creating a hole in it, without physically touching the embryo.
More often it is observed that not all embryos are able to hatch or rupture in time, either because the outer layer (zona pellucida) is too thick or the embryos lack the competence (insufficient energy) to rupture. To tackle this issue and increase the chances of successful implantations, embryos are graded before they are selected for embryo transfers or embryo freezing (cryopreservation). Embryos that display thicker outer layers or less energy are then considered as potential embryos for assisted hatching.