Pregnancy may not occur even though good quality embryos are obtained and transferred in IVF treatments. One of the reasons is that the membrane surrounding the embryo does not tear and the embryo cannot hold onto the uterus. For this purpose, we apply membrane thinning or completely opening method to embryos on the 2, 3 and 4 days before transfer. The process can be carried out in 3 different ways: mechanical, acid solution and laser. We prefer laser method because it is easy to apply and takes less time.