Hatching occurs naturally when embryos are in a woman’s uterus. It takes place five or six days after fertilisation, when the developing embryo ‘escapes’ from the zona pellucida (the embryo ‘shell’).
Once the embryo has successfully hatched, it can make contact with the lining of the uterus, known as the endometrium. Some embryos will then implant and continue to develop into a pregnancy. If an embryo cannot hatch, then it is impossible for it to implant and for pregnancy to occur.
Assisted hatching is a laboratory technique to enable embryos to hatch successfully.
A small gap is made in the zona pellucida or an area of the zona pellucida is weakened/thinned – mechanically (Mechanical Dissection Pipette), chemically (using Acid Tyrode’s solution) or by using a laser (eg Saturn 5™) to allow the embryo to ‘hatch out’ through the treated area.
• Advanced maternal age (older than 39) • Thickened zona pellucida • Where embryos are thought to lack sufficient energy to complete the hatching process • Two or more failed IVF cycles • Poor embryo quality • Post vitrification