Assisted hatching is a laboratory technique that consists of making a small hole in the zona pellucida, the membrane surrounding the embryo, in order to make it easier for the embryo to hatch out (something that naturally needs to happen) and implant in the uterus.
Assisted hatching is mainly used:
- To encourage embryo implantation in cases of recurrent embryo failure
It is advised in couples who have gone through several transfers of good quality embryos but that have failed to implant. Assisted hatching aims to help the embryo break away from the zona pellucida and hatch in the uterus more easily.
- As part of the process of studying embryo genetics
Making a hole in the zona pellucida in the embryo means that a few cells can be obtained and they can be genetically analysed before transferring embryos to the uterus.
Assisted hatching can also be used in cases such as the following:
- Transfer of cryopreserved embryos. Some studies suggest that the freezing process hardens the zona pellucida.
- Embryos with a larger than normal zona pellucida since this may make it difficult for the embryo to hatch out.
- Embryos taken from older patients since they tend to have a harder zona pellucida, making them more difficult to break.
Several techniques can be used in assisted hatching although there are two main ones: chemical agents such as acid Tyrode’s or laser beams. The latter is very precise, quick and safe for the embryo. It is the technique of choice in our laboratory where the very latest laser systems are used.