Laser Assisted Hatching (LAH) is a form of micromanipulation. Unlike ICSI, LAH focuses on the embryo rather than the egg. During development, embryos are surrounded by a protective coating called the zona pellucida. It protects the embryo until it “hatches” from the zona to allow implantation in the uterine cavity. In certain circumstances the embryo cannot “hatch” out effectively. Hatching with the laser has been shown to increase pregnancy rates for patients.
LAH is helpful in cases where there may be an expected problem for the embryo to break out of its shell, the zona pellucida. This includes patients with advanced maternal age, failed cycles and abnormal hormone levels (elevated FSH). It is now used prior to all freezing of embryos and with frozen-thawed embryo cycles. It is also used wehn there is suboptimal embryo quality.
A laser is used to introduce a small opening in the zona pellucida. Introducing this opening can facilitate the embryo’s release from the zona pellucida. LAH is performed at the time of embryo transfer.This may result in increased implantation in the uterus. Literature data suggests higher rates of clinical pregnancy and implantation if embryos are hatched.
Additionally, the laser is used to “collapse” or “shrink” expanded blastocysts at the time of cryopreservation.Literature suggests that artificial shrinkage of expanded blastocysts prior to cryopreservation results in higher implantation rates.
Known potential disadvantages of LAH include, but are not limited to the following:
- This method may yield an increased potential of identical twins.
- The hole in the zona may decrease the protective effect for the embryo.
- The method may rarely cause the embryo to degenerate.
- Technical problems may exist which may make the method impossible in some case(s).