During the IVF process, one egg is fertilized by one sperm in the laboratory. Once the fertilization process is complete, the resulting ‘zygote’ or one-cell embryo begins to divide. In this early stage, the embryo is contained within a protective shell called the zona pellucida. In order for the embryo to attach and implant into the uterine lining, it must “hatch” out of the zona pellucida.
Studies have shown that successful hatching and implantation (attachment to the uterine lining) of the embryo may be related to a patients’ age, thickness of the zona pellucida, developmental capacity of the embryo, and zona pellucida hardening from cryopreservation. In select patients, many IVF laboratories recommend performing a procedure called ‘assisted hatching’ in order to improve embryo hatching and implantation. Assisted hatching is usually accomplished with a laser to make a small opening in the zona pellucida of embryos for patients over the age of 37, patients who have previously failed IVF and embryo transfer, patients with embryos having excessively thick zona pellucidae, and patients using frozen eggs or embryos.
In the hands of an experienced embryologist, laser-assisted hatching is safe and effective in improving patient success following embryo transfer.