What is assisted hatching?

The egg and early embryo are surrounded by a thick layer of special proteins called the zona pellucida. Before an embryo can implant in the womb it has to break out or ‘hatch’ from its zona pellucida. Some people think that assisted hatching – using acid, lasers or other tools to thin or make a hole in the zona pellucida – helps the embryo to ‘hatch’.

Risks of assisted hatching

There is always some risk of damaging embryos with these types of procedures although this is unusual (less than 5%) Evidence The National Institute for Clinical Excellence (NICE) does not recommended assisted hatching as it has not been shown to improve pregnancy rates.

NICE also says that further research is needed to find out whether assisted hatching influences birth rates and to examine the consequences for children born as a result of this procedure. There have been eight RCT studies considered for this technique including chemical and laser hatching. All of them have shown similar results suggesting that clinical outcomes were the same.

Some clinics believe assisted hatching can lead to higher birth rates in specific subgroups of patients. There is however no good quality evidence to support the use of assisted hatching for any patient.

Current HFEA grading

For more information, please visit the HFEA website