What Is Assisted Hatching?
Achieving conception is only the first step in becoming parents, and it doesn't guarantee a baby. One in four known pregnancies ends in miscarriage, and there are many other pregnancies which stop before the mother even realises she was pregnant. Human reproduction is a fragile and delicate thing which can go wrong at any time.
After conception has taken place, the embryo first has to 'hatch' out of a gel like substance known as zona pellucida before it can implant into the lining of the womb. While this substance is vital and a part of the egg (it allows only 1 sperm to penetrate at fertilisation), it outlives its usefulness and breaks down.
Sometimes, however, the zona pellucida is abnormally thick, preventing the embryo from hatching out. This means the embryo cannot implant into the womb and a miscarriage occurs. This medical problem is called 'implantation failure' and is more commonly experienced by older women, although it can happen in any age group.
Assisting hatching is when an embryo is fertilised outside the womb via IVF and the embryologist makes a tiny hole in the zona pellucida to make the hatching process easier, before transferring it to the womb. Usually this is done by applying an acidic chemical.
New Techniques
Recently, the Centre for Reproductive Medicine in Bristol, UK, has been the first fertility clinic to perform assisted hatching by the use of a laser.
Staff at the clinic say that using a laser to break the zona is safer and they have also noticed increased pregnancy rates in older women.
In a 2005 study in 'Reproductive Biomedicine', a sample of 150 people with previous implantation failure were treated with intracytoplasmic sperm injection and divided into two groups, one with only one previous implantation failure, and group two, with several implantation failures. In group two, those patients who had had laser assisted hatching had a significantly higher rate of pregnancy than those who didn't (10.9% for those who had laser treatment as opposed to 2.6% for those who didn't).
Reproductive BioMedicine Online, Volume 10, Number 2, February 2005 , pp. 224-229(6)
Is Assisted Hatching Safe?
This procedure carries a risk of damage to the embryo and may possibly result in an embryo which is not viable. There are no additional risks to the woman, other than those she would already experience as an IVF patient.
Who is The Treatment Most Suited To?
Older women, women who have suffered repeated implantation failure, those who have suffered several miscarriages, during IVF where the embryos selected for transfer, appear to have a thickened zonae, couples who are attempting pregnancy with frozen embryos and couples who have had failed IVF cycles.
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