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Assisted Hatching in IVF: What You Need to Know

Assisted Hatching in IVF

If your fertility specialist has recommended assisted hatching as part of your in vitro fertilization treatment, there are some key factors to understand before the procedure.

In vitro fertilization (IVF) is an infertility treatment for those who are having difficulty conceiving, who are diagnosed with medical conditions that affect the uterus or sperm, and for people who may want to prevent specific genetic conditions from being passed on to a child.

A form of assisted reproductive technology (ART), the goal of assisted hatching is to improve the chances of an embryo implanting. Assisted hatching is most often recommended for women who have had one or more failed IVF cycles.

What Is Assisted Hatching?

Before we delve into the process of assisted hatching, it’s important to first understand how implantation occurs. In a natural pregnancy, an egg is released from the ovaries and fertilized by a single sperm, creating an embryo. This embryo is surrounded by a hard outer layer of cells called the zona pellucida. In order for the embryo to implant in the uterine lining, it must first break free from this outer “shell”. This is known as “hatching”.

Oftentimes, the zona pellucida is thicker than usual and may need to be manually stimulated to break away from the embryo. This is why assisted hatching is used.

During an IVF treatment, the eggs and sperm are combined in a laboratory to increase the chances of successful fertilization. As the embryos are monitored over several days, an embryologist will create a small crack in the zona pellucida to help the embryo break free for implantation. Assisted hatching is performed on the third day of embryo development as natural “hatching” usually occurs between days 5 and 7 of development.

Who Might Benefit from Assisted Hatching?

Assisted hatching is recommended for patients who are undergoing IVF treatment for the second or third time due to failed cycles. It’s also used for couples who cannot naturally conceive, either due to various medical conditions or reproductive damage.

Below are some other situations where assisted hatching can be beneficial.

  • Age of the woman undergoing IVF: Women older than 36 years of age may benefit from assisted hatching as the zona pellucida can thicken as we age. Just as the quantity of our eggs decreases over time, the quality of the eggs may also cause fertility issues.
  • Repeated implantation failure in previous IVF cycles: Whether the reason for infertility can be explained or not, oftentimes, repeated IVF cycles may not be successful. Assisted hatching may help increase the chances of a successful pregnancy even with an inexplicable case.
  • Thickened zona pellucida: Abnormalities with the structure of the zona pellucida can impede the chances of successful implantation. A thick or hard protective shell surrounding the embryo can be linked to increased levels of follicle-stimulating hormone (FSH).
  • Frozen-thawed embryos: Using embryos that have been previously frozen can pose challenges in fertilization. Assisted hatching is done on thawed embryos as the zona pellucida can be hardened during cryopreservation, regardless of the development stage during freezing.
  • Other specific fertility issues: As IVF treatment is personalized for each patient, assisted hatching is designed to help with a number of medical concerns. These involve but are not limited to, excessive fragmentation, slow division rates, and other embryo-related conditions.

What Are the Risks and Benefits of Assisted Hatching?

There are many pros and cons to assisted hatching. Assisted hatching has been shown to increase the rate of successful implantation and pregnancy. Up to 38% of embryos created through IVF with assisted hatching result in pregnancy, with implantation as high as 50%.

But, just like any other medical procedure, there are risks. Successful assisted hatching depends not only on the embryo’s response but also on the skills of the embryologist performing the procedure. An embryo is susceptible to damage if the technique is not seamless or if the zona pellucida is handled poorly.

Assisted hatching can weaken the embryo’s protective shell to the point where infection may develop. A pregnancy may also result in multiple births or birth defects in extremely rare cases.

Of course, as with any IVF treatment, there is no guarantee of success even with assisted hatching. There is continuous research on the effectiveness of using ART including assisted hatching. While the laser-assisted hatching technique has been employed in the majority of fertility clinics, most of the findings have concentrated on the effectiveness of using earlier techniques of acidified Tyrode solution or partial ZP dissection.

What to Expect if You Choose Assisted Hatching

The following steps are involved during an IVF treatment that uses assisted hatching:

  • On day three of embryo development, the embryo is removed from the laboratory incubator and contained within a cylinder or pipette. A solution is then added to the pipette to weaken the zona pellucida. It is then carefully rinsed and returned to the incubator. If the laser technique is used, a small hole is formed in the outer shell of the embryo.
  • As with any form of fertility treatment, undergoing IVF and assisted hatching procedures can cause emotional challenges for those involved. Anxiety and hopefulness can give way to sadness, grief, and anger if the treatment is unsuccessful.

Make Informed Decisions on Your IVF Journey with ONE Fertility Kitchener Waterloo

If you are looking for more information on IVF and assisted hatching, speak to the specialists at ONE Fertility Kitchener Waterloo. All of our IVF services are performed onsite and will be customized to your specific needs. For more information on our compassionate and personalized fertility plans, contact us at (519) 650-0011 or email us at We can support you on your journey to parenthood.


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Kitchener, ON
N2P 2X7

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