In Vitro Fertilization
Assisted Hatching
Embryos are surrounded by a thin shell called the zona pellucida. For pregnancy to occur, the embryo must shed the zona pellucida. This “hatching” usually occurs around day 5-7 due to contraction and expansion of the embryo. We can assist this hatching by making the zona pellucida thinner.
Assisted hatching is a microscopic laboratory procedure designed to increase the chances of pregnancy by thinning out the zona pellucida. This thinning can be accomplished in several ways: with a laser, with proteolytic enzymes or with an acidified Tyrode’s solution.
When performed on day 3 embryos, there are no known risks to assisted hatching. When performed on day 5 embryos, there is an increased risk of identical twins.
Assisted hatching is indicated in women:
• age 37 or older
• with previous IVF failures
• whose embryos have a thick zona pellucida
• embryos with multiple fragments surrounding the cells