An unsuccessful round of in vitro fertilization (IVF) is frustrating & discouraging for patients as well as their care team, especially after several attempts. A common reason that IVF is unsuccessful is that the embryo fails to implant properly in the uterus.
One of the methods that is used to help improve implantation rates is known as ‘assisted hatching’. Assisted hatching may be recommended to those who have experienced multiple failed IVF cycles as an additional process in an attempt to increase IVF success.
What is Assisted hatching?
When an embryo is formed, both naturally or through IVF, it is surrounded by a matrix of proteins known as the zona pellucida. In order for implantation to occur, the embryo must hatch from it’s protein shell.
Assisted hatching is a lab technique done by embryologists to create a small opening in the zona pellucida allowing the embryo to hatch more easily. There are many methods for an embryologist to use when performing assisted hatching procedures, though the most commonly used is laser-assisted hatching.
Some examples of assisted hatching methods include:
Does assisted hatching affect the implantation of the embryo?
In the past, assisted hatching was a controversial subject. Some thought that manually removing an embryo’s protective shell might make it more susceptible to damage. However, studies have recently shown that removing this layer is a perfectly safe procedure because the shell is not a living component of the embryo. Laser hatching appears to be superior to chemical hatching, where a small amount of acid is applied to the embryo’s shell. The use of laser technology increases the precision of the removal while minimizing heat exposure and duration of the procedure, significantly eliminating any risk of embryo damage.
Benefits of Assisted Hatching
Assisted hatching has been shown to improve implantation and clinical pregnancy rates. It has also been shown that assisted hatching can allow an embryo to implant a day earlier than embryos that hatch naturally. However, assisted hatching has not yet been shown to improve live birth rates, and more research is still needed in this area. Research also indicates that assisted hatching is much more beneficial for those with poor prognosis over those with a good prognosis. For this reason, assisted hatching is not recommended for everyone.
Who is assisted hatching recommended for?
There are many reasons as to why an embryo may have a thicker zona pellucida, and therefore more difficulty hatching naturally. Some reasons that the zona pellucida may be thicker are: advanced age, elevated FSH, and fertility medications. Assisted hatching has been shown to increase clinical pregnancy rates in:
Women over the age of 37
Patients who have experienced two or more IVF failure
Women with high levels of follicle stimulating hormone (FSH)
Patients with poor embryo quality
Are there any risks?
Any type of interference with an embryo comes with a level of risk as there is a possibility of damaging the embryo.
While not common, risks of assisted hatching include:
Tampering with the natural hatching process, and the embryo failing to fully hatch even with assistance
Irreparable damage to the embryo making it non-viable for transfer
Monozygotic twinning, where the embryo separates to create two identical fetuses. This is very rare, seen in less than 1% of cases
A Final Word: is assisted hatching right for you?
When going through IVF treatments, it is often tempting to want to apply all the possible processes & procedures. However, more intervention will not necessarily lead to higher chances of success.
Assisted hatching is a procedure that is not required for everyone and should only be offered to specific patients based on their particular medical & fertility history. It is important to talk to your doctor in order to determine what is best for you.
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