Assisted hatching is a small medical procedure carried out during In Vitro Fertilization (IVF) to increase success rate of IVF. Couples with poor or problematic reproductive capabilities resort to IVF to conceive. Assisted hatching is usually carried out when the female partner is in the age group of 35 to 39, the quality of eggs or embryos produced by her are of poor quality, or when couples have had multiple instances of failed IVF procedure.
Understanding Assisted Hatching
When formed, human embryos are covered with a protein protective layer known as zona pellicuda. The embryo can implant itself in the uterus only if it can hatch out or break out of this layer. At times, embryos produced during IVF find it difficult to hatch out of zona pellicuda because of its toughness. Under such circumstances, assisted hatching procedure is done to assist the embryo in hatching by creating a small hole in its outer lining.
Chemical Procedure of Hatching
The thickness of the embryo wall is assessed, and if it found to be thicker than normal, assisted hatching is performed. It is a very delicate process done with immense skill of micro-manipulation technique. Assisted hatching is carried out on the fourth day of the development of the embryo. In this, the embryo is taken in a petri dish having culture solution. The embryo then is held in position with the help of a special pipette. A fine micro-manipulation hollow needle with a dilute acidic solution is held next to the zona pellicuda layer of the embryo by the embryologist. A bit of the acidic solution is then released by the embryologist so that it touches the zona pellicuda. On coming into contact with the acidic solution, zona pellicuda develops a small hole at the point of contact. After this, the embryo is washed in a special solution and kept in an incubator until the transfer of the embryo takes place.
Types of Assisted Hatching
The process of assisted hatching is done through three processes namely: Laser, Chemical and Mechanical methods. In the laser method of assisted hatching, special laser is used for perforating zona pellicuda. In the mechanical method, zona pellicuda is pierced open while in chemical method (an acidic solution does the job).
Though assisted hatching increases the implantation success rate with fewer embryo transfers, it can result in the formation of identical twins due to the splitting of embryo into two identical halves. It can also result in fetal complications like physical deformity, conjoined twins or embryo damage. On the other hand, the mother can also develop infection, nausea, mood swings or hypertension due to hormonal changes. Considering all these factors, assisted hatching is performed only in extreme cases of IVF failures.
Assisted hatching is ideal for you only if you fall in the age group of 35 to 39. Women in this age group tend to have elevated follicle stimulating hormones (FSH) levels and hardening of the zona pellicuda (and only for these mothers assisted hatching is used). Studies show that success rate of IVF, along with assisted hatching, is about 49 percent in this age group. Success rates also depend on the skills of the micro-manipulation of an embryologist.