Early embryos are surrounded by an outer coating called the zona pellucida. The zona holds the cells of an
embryo together. After an embryo arrives in the uterus, the outer zona coating dissolves. This allows the embryo
to "hatch" and grow larger. Implantation cannot occur until the embryo hatches.
Natural hatching is less likely to occur for certain women. A process called assisted hatching (AH) may help
embryos from these women implant in the uterus during an in vitro fertilization (IVF) cycle. Embryo implantation
is one of the greatest barriers to success for IVF cycles.
|
The most commonly used indications for assisted hatching with an in vitro fertilization case are:
Age factor - Couples having IVF with the female partner's age over 37
Egg quantity and quality factor - Couples in which the female's day 3 follicle stimulating hormone (FSH) level is elevated
Embryo quality factor - Couples having IVF with poor quality embryos (excessive fragmentation or slow rates of cell division)
Zona factor - Couples having IVF with embryos that have a thick outer shell (zona pellucida)
Previous failures - Couples having IVF that have had one or more previous IVF cycles that failed
Just prior to beginning the hatching process on an 8-cell embryo
Holding pipette on left holds embryo in place
Hatching is done by injecting a solution through the hollow
needle on the right
Some cumulus cells from the ovary are stuck to the
embryo's shell at 4 to 6 o'clock
Hatching a high quality 8-cell embryo
A small opening is being made in the embryo's shell (zona
pellucida)
The needle has been further advanced through the
embryo's shell
A gap in the shell is developing
A gap in the zona has been created
The oolemma (egg membrane) is bulging and about to "pop"
When it pops - assisted hatching is complete
Hatching completed
Assisted Hatching
