The covering over the embryo is called zona pellucida. It’s main function is to protect the embryo and maintain its integrity as it travels through the oviduct into the uterine cavity . Once it reaches the cavity blastocysts must get out of the ZP ( hatching )so that the trophectoderm cells can interact with the Endometrial cells and implantation can occur .
Zona hardening occurs after fertilisation and this is a physiological phenomenon to prevent polyspermy and ensure embryo protection during transport through the reproductive tract .
Why and when do we perform assisted hatching at Anmol Fertility and IVF centre ?
Embryos with thick zona or those that present extensive fragmentation after freezing and thawing may benefit from AH .Day 3 or Day 5 embryos are placed in Heppes medium , layered with oil , on a heated stage and a hole is created in the ZP , large enough to avoid trapping of the embryo but not so large that it permits blastomere loss. Monozygotic twinning has been described as a consequence of AH . 30 minute period of culture before transfer of the manipulated embryos is enough .
Partial zona dissection : microneedle is used to create a hole between 11 o clock and 1 o’clock position .
Acid Tyrolese assisted hatching : Zona hardening and increase in volume of perivitelline in zygotes and embryos allows effeicient and safe use of acid Tyrolese solution in embryos for ZP drilling compared with Oocyte.
Limited exposure to Acid Tyrodes is necessary to avoid harmful effects on Embryo development .
Laser assisted hatching :
Our team of experts at Anmol Fertility and IVF centre uses it accurately and quickly , to produce photoablation of the ZP .
We have seen that AH improves the pregnancy and implantation rate in patients with previous implantation failures but we don’t currently recommend it as a routine technique in patients undergoing ART .