Opening of embryo membrane or assisted hatching

Assisted hatching of embryo is a method of artificial opening of the embryo membrane which may improve the implantation of the embryo onto the endometrium of the uterus. It can be done both in IVF and ICSI treatments as well as in frozen embryo transfers. The embryo develops and divides into over a hundred cells surrounded by embryo membrane called zone pellucida.

The zona keeps thinning as the embryo continues to divide and finally ruptures so that the embryo gets out of its shell. Embryo hatching is the pre-condition of embryo implantation onto the endometrium of uterus. If the zona pellucida is thicker than normal, the rupture of the zona may be hindered, which prevents implantation. Hormonal treatments may also have an effect on the thickness and viscosity of the membrane of the embryo.

The membrane of the embryo can be thinned or a hole can be made with microscopic techniques. This is thought to help the embryo to hatch and thus improve the chance of implantation. Assisted hatching can also be used in cases where the implantation of the embryo did not occur in previous treatments. Assisted hatching is still a controversial method since the increased implantation rate has not been conclusively proved.