Laser Assisted Hatching / Zona Thinning

Laser Assisted Hatching / Zona Thinning

Maternal age is known to be one of the major factors influencing the outcome of IVF treatment. In some cases, this may be due to changes in the uterus.

“Studies have shown, however, that women over the age of 40, who receive eggs from young donors, can achieve comparable pregnancy rates to younger women”

This demonstrates that the age of the egg also plays an important role in determining the chances of conception.

Hardening and thickening of the zona pellucida (the shell around the egg) is thought to occur more frequently in older women. This hardening of the zona pellucida may inhibit the natural hatching of the embryo, the process necessary for implantation to take place. Methods to assist this natural hatching have been developed over the last decade and have involved the making of a hole in the shell of the egg, by chemical means, or thinning a portion of the shell of the egg by the use of a laser.

“At the Harley Street Fertility Centre we are now using a laser system for Assisted Hatching”

Originally we used the chemical method but now that highly efficient and more cost effective lasers have been developed, we believe that this offers an improved chance of success. 

The risks associated with assisted hatching have largely been those caused by premature hatching, as the zona is essential in the first few days of the embryo’s development. The laser minimises this danger. The method we now prefer involves thinning the shell, by about 80%. This is done over an area of 55-70mm, around the perimeter of the zona, without it actually being breached. Fears about the heat generated by lasers have also been overcome as the latest systems fire a precisely focused laser for just a few milliseconds.

There is also potentially a slightly increased risk of identical twins following hatching. When advised Assisted Hatching will be fully discussed at consultation and thereafter any concerns can be raised with consultants or embryologists.