A small hole is made in the zona pellucida, using a micromanipulation, thereby facilitating for zona hatching to occur. Zona hatching is where the blastocyst (D-5 embryo) gets rid of the surrounding zona pellucida to be able to implant in the uterus. Zona hatching is related to increased rates of clinical pregnancy and multiple pregnancy in women with previous repeated ART failure or frozen-thawed embryos.
