For an embryo to implant into the lining of the uterus, it must essentially divide to where it forms a multi-cell embryo with a fluid cavity (blastocyst). This blastocyst is coated with a gel-like material called ‘Zona’ or ‘Zona Pellucida. In order for the blastocyst to implant into the uterus, its cells must break through Zona. This process is known as hatching.
Quite often this ability of blastocyst by IVF or ICSI to hatch is impaired. This is when Assisted Hatching India becomes useful. It is a laboratory procedure where Zona of the early embryo is chemically or mechanically weakened in ways that assist the embryo in hatching more easily allowing implantation into the lining of the uterus. It is now also widely accepted that Assisted Hatching improves rates of implantation in certain patients undergoing IVF or ICSI or both.
Who Should Consider Assisted Hatching
Age Factor: especially when female partner is older than 37 years
Egg Quantity & Quality: when woman’s day 3 Follicle Stimulating Hormone (FSH) level is elevated, or with low Antral Follicle Count or low AMH level
Embryo Quality Factor: poor quality of embryos with slow rates of cell division or excessive fragmentation
Zona Factor: when embryos have a thick Zona Pellucida or thick outer shell
Previous IVF Failures: with women who have had one or more previous IVF cycles failed
Assisted Hatching with IVF procedure`
One of the most frustrating aspects of IVF procedure for patients & professionals alike is coping with failure, especially for couples who have attempted ART procedures several times. Assisted Hatching helps cope with such difficulties for couples who are also running out of time. After observing that embryos with thin ZP had higher rates of implantation, it was postulated that creating a minor defect in ZP will eventually increase chances of embryo hatching. This came as a blessing for women who faced multiple failures in IVF cycles because of a thicker Zona shell impairing hatching. Additionally, assisted hatched embryos implant a day early which allows a greater opportunity for the implant to occur, especially in cases where the endometrium is advanced due to ovarian stimulation. This extra laboratory manipulation nevertheless involves a small amount of risk of damage to the embryo during the processes of micromanipulation & transfer, alongside a slight increase in identical twins. The size of the defect is, however, critical in this procedure & may produce undesired results.
Types of Assisted Hatching
There are four types of Assisted Hatching India techniques presently being practiced by ART specialists around the world.
- Partial Zona Dissection Also known as Mechanical Assisted Hatching, Partial Zona Dissection involves briefly holding the embryo in position by gentle suction. The micro-needle is passed through ZP at the largest perivitelline & advanced tangentially. The embryo is subsequently released from holding pipette after creating a cross-shaped slit. Embryos are subsequently returned to culture 7 stored until transfer.
- Acid Tyrode Assisted Hatching A defect is created in the Zona of the embryo by using a mouth-controlled delivery system to blow acid Tyrode over external surface. Embryos are subsequently rinsed several times to wash excess acid before returning to standard culture media & stored until transfer.
- Laser Hatching A computer-controlled non-contact mode is used in this method for piercing the Zona. Laser Assisted Hatching involves a specific software designed to enable easy positioning, focus & measurement of embryos alongside simple alignment of the laser. The laser is also organized with three preset energy intensities of low, medium & high which can deliver a single pulse with a single click of the mouse to perforate the Zona as per specific requirements.
- Assisted Hatching by Pronase Thinning of Zona Pellucida A dilute solution of pronase is used in this procedure. The embryos are transferred to pronase solution in a G2 medium under oil for initial stretching & softening of ZP. The aim of this method is to thin ZP without complete removal. Subsequently observed under the microscope for results, the embryos are further incubated with pronase if required. These embryos are then transferred to fresh G2 medium & washed twice before being placed into the incubator until transfer.
Assisted Hatching Success Rates
It is important that Assisted Hatching India is performed by properly trained expert embryologists for success. Actual live birth rates from this ART procedure will differ from IVF clinic to clinic. As female fertility diminishes with age, the younger you are, higher the chances of success. Research suggests that this procedure is no more likely to cause abnormality than IVF without Assisted Hatching.