During IVF, every step of embryo development matters. One part of the process you may hear about is called assisted hatching — a laboratory technique that may be used in certain situations to support implantation.

While assisted hatching can sound highly technical, the idea behind it is actually simple.

What Is Assisted Hatching in IVF?

Early in development, an embryo is surrounded by a thin protein layer remaining from the egg, called the zona pellucida. You can think of this as a protective shell.

Before an embryo can implant into the uterine lining, it must naturally break out, or “hatch,” out of this shell. If hatching does not happen properly, implantation does not occur.

Assisted hatching is an embryology lab procedure in which an embryologist creates a tiny opening in the protective shell — most often using a precise laser — to help the embryo hatch more easily.

This is usually done on:

• Day 3 embryos, or
• Day 5–6 embryos (blastocysts)

The embryo is then returned to the incubator and later transferred to the uterus.

Why Do Some Embryos Have Trouble Hatching?

Some embryos may have a thicker or less flexible outer shell. Researchers believe this may occur more often in:

• People of advanced reproductive age
• Embryos that develop more slowly
• Certain IVF cycles after freezing and thawing

In these cases, assisted hatching is thought to potentially make it easier for the embryo to implant.

Does Assisted Hatching Improve IVF Success Rates?

This is where things become more nuanced.

Early studies suggested assisted hatching might help improve pregnancy rates, particularly in people with prior failed IVF cycles. However, more recent and higher-quality research shows that assisted hatching does not clearly improve live birth rates for most patients.

Major reproductive medicine organizations, including the American Society for Reproductive Medicine (ASRM), state that:

• Assisted hatching should not be used routinely for all IVF patients
• Evidence is mixed for people with a poorer prognosis
• It has not consistently improved live birth rates in fresh or frozen embryo transfers

This does not mean it never helps — it means the benefit appears to be limited to certain situations, and doctors individualize the decision.

Who May Benefit From Assisted Hatching?

Your fertility team may discuss assisted hatching if you:

• Are of advanced reproductive age
• Have had multiple failed IVF cycles
• Have embryos with certain lab characteristics
• Are undergoing embryo testing, which already requires opening the shell

In these cases, assisted hatching may be considered as one piece of a broader strategy.

Is Assisted Hatching Safe? Risks to Know

When performed by experienced embryologists, assisted hatching is generally safe. Still, as with any laboratory procedure, there are small risks, including:

• Possible embryo damage
• A potential change in the chance of identical twins (research is mixed)

Because benefits are uncertain for many patients, doctors carefully weigh these risks and benefits before recommending it.

The Bottom Line: Is Assisted Hatching Right for You?

Assisted hatching is a lab technique designed to help embryos break out of their protective shell before implantation. While it may be helpful in select cases, research shows it does not consistently improve live birth rates, and it is not recommended for routine use in all IVF cycles.

If your clinic suggests assisted hatching, it’s reasonable to ask:

• Why it may help in your case?
• What the clinic’s experience is?
• How does it fit into your overall treatment plan?

IVF success depends on many factors — embryo health, uterine receptivity, and timing — and assisted hatching is just one possible tool.

This information has been medically reviewed by Tendai M. Chiware, M.D. the Director of the Third Party Reproduction Program at Genesis Fertility