One of the most common reasons for an IVF cycle to fail is because the embryo/s have failed to implant. An embryo must hatch out of its shell in order to implant into the lining of the uterus. This usually occurs five days after fertilisation.
During fertilisation the sperm must penetrate the hard shell surrounding the egg. This hard shell is called the zona pellucida. Once the sperm has penetrated the egg, the zona hardens again to prevent any additional sperm from entering the egg. During the following days the embryo undergoes a series of development stages, from zygote to morula to blastocyst. In nature this development occurs in the fallopian tubes and when the embryos reach the blastocyst stage they leave the fallopian tube and enter the uterine cavity.
In order to implant into the uterine lining, the embryo must hatch out of its shell, the zona pellucida. If hatching does not occur the embryo cannot implant and pregnancy will not occur. A common cause of difficulties with hatching is that the shell is too thick or too hard.
In assisted hatching a small break is made in the zona pellucida to weaken it just prior to blastocyst transfer. In specific cases this results in increased implantation of the blastocyst into the endometrium and increased pregnancy rates.
At Medfem we employ assisted hatching in cases such as advanced reproductive age, elevated FSH, decreased ovarian reserve, thickened zona, and prior implantation failure.