![Laproscopy Surgeon in Meerut](img/medical/hatching.jpg)
Assisted Hatching
Most people are familiar with the fact that most couples, who reach the point in an ART cycle when embryos are transferred to the uterus, will not achieve a pregnancy. Even when presumably high quality, fertile eggs are used, such as in egg donation, over half of couples are still left disappointed each cycle. Since most couples are able to get eggs and have fertilization, then the question is where does the failure occur? The answer may be in the implantation phase.
After a fertilized egg is returned to the uterus, several things must happen:
It must continue to divide and grow (it is now called an embryo).
The embryo must break out of the zona pellucida (usually just called the zona) which is a hard protein shell that surrounds it.
The embryo must then burrow into the lining of the uterus (called the endometrium) and continue to grow there.
It is the published opinion of some scientists that, pregnancy may fail to occur in some cases because of an inability of the embryo to break out or "hatch" from the zona. According to the theory, there are some women who are more prone for this to happen.
These include women who: -- Are over 40 years old -- Have failed to implant in several IVF cycles. -- Have eggs with very thick zona when measured under the microscope and -- who have abnormal hormone profiles indicative of lower quality eggs (elevated FSH levels)
Logically then, if we could assist those embryos in the hatching process, it might be possible to increase the chance that implantation and hence successful pregnancy might occur. And so assisted hatching (AZH) was invented.
The assisted hatching procedure involves thinning or making a small hole in the zona pellucida that surrounds the embryo (a protective layer). There some evidence that assisted hatching may improve implantation rate. Before an embryo implant into the uterus it must hatch from the zona pellucida. There is some evidence that in some women the zona becomes toughened, restricting the embryo to hatch. Making a small hole in the zona using a micromanipulation, this may make it easier for hatching to occur.
How is assisted hatching is performed
Just before the embryos are replaced, whether they are fresh or frozen/thawed, a small hole is made in the zona, or by thinning it using a micromanipulation technique. The process is repeated for each embryo. The main methods currently in use for assisted hatching are: chemical, mechanical and laser. The process will damage about 1% of embryos.
Most IVF clinics will not perform assisted hatching if there is one embryo available because of possible damage to this embryo would result in no embryo transfer. The assisted hatched embryos are then transferred into the uterine cavity as usual. Some clinics will give the woman a course of antibiotics to prevent infection. (Assisted hatching deprives the embryo of its intact protective coat, which shields it from exposure to any harmful factors in the uterus). Assisted hatching has been implicated in an increased rate of monozygotic twins.
Success rates after assisted hatching
The success rate of assisted hatching varies widely between different clinics. This could be due to differences in their patient populations, experienced and the technique used for assisted hatching. Some clinics reported no benefit when assisted hatching was offered to all patients, while others reported significant increases in clinical pregnancy and implantation rates following assisted hatching when the procedure was performed in selected groups of patients.
To whom assisted hatching may be advised?
Women over 39 years and using their own eggs.
Women who had recurrent failure of embryo implantation (three or more embryo transfers without a pregnancy).
Women whose embryos exhibit thick zona pellucida.
Women with elevated FSH levels.
After a fertilized egg is returned to the uterus, several things must happen:
It is the published opinion of some scientists that, pregnancy may fail to occur in some cases because of an inability of the embryo to break out or "hatch" from the zona. According to the theory, there are some women who are more prone for this to happen.
These include women who: -- Are over 40 years old -- Have failed to implant in several IVF cycles. -- Have eggs with very thick zona when measured under the microscope and -- who have abnormal hormone profiles indicative of lower quality eggs (elevated FSH levels)
Logically then, if we could assist those embryos in the hatching process, it might be possible to increase the chance that implantation and hence successful pregnancy might occur. And so assisted hatching (AZH) was invented.
The assisted hatching procedure involves thinning or making a small hole in the zona pellucida that surrounds the embryo (a protective layer). There some evidence that assisted hatching may improve implantation rate. Before an embryo implant into the uterus it must hatch from the zona pellucida. There is some evidence that in some women the zona becomes toughened, restricting the embryo to hatch. Making a small hole in the zona using a micromanipulation, this may make it easier for hatching to occur.
How is assisted hatching is performed
Just before the embryos are replaced, whether they are fresh or frozen/thawed, a small hole is made in the zona, or by thinning it using a micromanipulation technique. The process is repeated for each embryo. The main methods currently in use for assisted hatching are: chemical, mechanical and laser. The process will damage about 1% of embryos.
Most IVF clinics will not perform assisted hatching if there is one embryo available because of possible damage to this embryo would result in no embryo transfer. The assisted hatched embryos are then transferred into the uterine cavity as usual. Some clinics will give the woman a course of antibiotics to prevent infection. (Assisted hatching deprives the embryo of its intact protective coat, which shields it from exposure to any harmful factors in the uterus). Assisted hatching has been implicated in an increased rate of monozygotic twins.
Success rates after assisted hatching
The success rate of assisted hatching varies widely between different clinics. This could be due to differences in their patient populations, experienced and the technique used for assisted hatching. Some clinics reported no benefit when assisted hatching was offered to all patients, while others reported significant increases in clinical pregnancy and implantation rates following assisted hatching when the procedure was performed in selected groups of patients.
To whom assisted hatching may be advised?