Assisted hatching is done while the embryo is in the laboratory.
Before being transferred back to the womb a hole is made in the outer layer of the embryo or it is thinned, using acid, laser or mechanical methods.
A typical procedure is:
Step 1. On day three of embryo development, the embryologist uses either a microlaser or a microtool to thin or cut a hole in the outer layer of the embryo.
Step 2. Because assisted hatching thins or makes a hole in the protective outer layer around the embryo, the woman may be given antibiotics to prevent infection.
How does assisted hatching work?
Before an embryo can attach to the wall of the womb, it has to break out or 'hatch' from its outer layer called the zona pellucida.
It has been suggested that making a hole in or thinning this outer layer may help embryos to 'hatch', increasing the chances of the woman becoming pregnant in some cases.
However, assisted hatching does not improve the quality of embryos.
What are the risks of assisted hatching?
Current research suggests that this treatment is no more likely to cause an abnormality to the baby than IVF without assisted hatching. As it is only the outer layer that is affected by this procedure, the embryo should remain unharmed.
There is always some risk of damage with any procedure of this type.
If you have more than one embryo transferred, this may increase the risk of multiple births.