What is Assisted Hatching?
In in vitro fertilization therapies, embryos resulting from fertilization are transferred to mother’s womb, where they continue growing and developing. However, pregnancy fails in some cases, even if high quality embryo is transferred. One of the underlying causes is the failure of rupture in the membrane that surrounds the embryo and thus, it cannot implant to endometrium.
Assisted hatching is thinning or creating a hole on the exterior coating of the embryo, a protective membrane called zona pellucida, at laboratory settings. This technique increases the chance of pregnancy especially at advanced age for women who are still at reproductive age.
What are Assisted Hatching Methods?
There are three major methods in assisted hatching.
Mechanical Assisted Hatching
In mechanical assisted hatching, a hole is created on the membrane, which surrounds the embryo that is immobilized with a holding pipette, using a micro-needle. Next, same procedure is repeated once more to create a linear opening on the membrane.
Chemical Assisted Hatching
This method is traditionally used and uses a type of acidic solution, called tyrode solution, to perforate the zona pellucida. Embryo is kept constant with a special holding pipette and a small hole is created on the embryonic surface by contacting the acid solution. Next, the embryo is washed and it stays in culture medium until it is transferred.
Laser Assisted Hatching
Laser procedure is most commonly preferred method for assisted hatching, as it is easier to use and takes less time. It is used in Day 3 or 5 embryos. A tiny hole is created on the zona pellucida or the embryo with laser beam soon before it is transferred to uterus. Next, embryo transfer is performed.
What are Indications of Assisted Hatching?
Assisted hatching is usually preferred in following cases;
- Patients older than 38
- Patients with thick zona pellucida
- Conditions leading to a problem in zona pellucida
- Couples with failed pregnancy attempts
- Patients with high FSH