Treatments
Blastocyst culture & assisted hatching
Blastocyst culture
Normally, following IVF or ICSI, an embryo transfer would be performed two days after egg collection (when the embryo contains two to four cells) or three days after (when the embryo contains six to nine cells). However, with improvements in culture media we now can culture embryos for five or six days more successfully than in the past. By this stage the embryos have numerous cells (approximately 100) and start to form two distinct layers. The embryos are then known as blastocysts and it is at this stage that embryos start to implant in the womb.
The consensus of thought at present is that if an embryo reaches the blastocyst stage outside of the body, it only has to endeavour to try and implant, whereas transferring the embryo on day three means that the embryo has to first try and develop to the blastocyst stage and then after this has to try and implant.
Assisted hatching
The most common reason for an IVF or ICSI cycle to fail is because embryos fail to implant. Before an embryo can implant into the lining of the uterus it must 'hatch' out of its 'shell'. This usually occurs five or six days following fertilisation.
There are many reasons why successful implantation does not occur. One of these reasons may be to do with the fact that the embryo is unable to 'hatch' because of the 'shell' (zona pellucida) is too thick, or too hard. Assisted hatching is a laboratory procedure whereby a hole is made in the 'shell' of a two or three-day embryo in order to help in the 'hatching' process and therefore, help with the implantation of the embryo in the endometrium. This two or three day old embryo is then placed back inside the womb.
