Assisted zona hatching (AZH) is a procedure of

assisted reproductive technology Assisted reproductive technology (ART) includes medical procedures used primarily to address infertility. This subject involves procedures such as in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), cryopreservation of gametes o ...

in which a small hole is made in the

zona pellucida The zona pellucida (plural zonae pellucidae, also egg coat or pellucid zone) is a specialized extracellular matrix that surrounds the plasma membrane of mammalian oocytes. It is a vital constitutive part of the oocyte. The zona pellucida first a ...

, using a micromanipulator, thereby facilitating

zona hatching Implantation (nidation) is the stage in the embryonic development of mammals in which the blastocyst hatches as the embryo, adheres, and invades into the wall of the female's uterus. Implantation is the first stage of gestation, and when success ...

.IVF-infertility.com
/ref> Zona hatching is where the

blastocyst The blastocyst is a structure formed in the early embryonic development of mammals. It possesses an inner cell mass (ICM) also known as the ''embryoblast'' which subsequently forms the embryo, and an outer layer of trophoblast cells called th ...

gets rid of the surrounding

to be able to

implant Implant can refer to: Medicine *Implant (medicine), or specifically: ** Brain implant ** Breast implant **Buttock implant **Cochlear implant **Contraceptive implant **Dental implant ** Fetal tissue implant **Implantable cardioverter-defibrillator ...

in the uterus.

Efficacy

A systematic review and meta-analysis came to the result that assisted zona hatching is related to increased rates of clinical pregnancy and multiple pregnancy in women with previous repeated failure or frozen-thawed embryos. However, it is unlikely to increase clinical pregnancy rates when performed in fresh embryos transferred to unselected women, to those without poor prognosis or to women of

advanced maternal age Advanced maternal age, in a broad sense, is the instance of a woman being of an older age at a stage of reproduction, although there are various definitions of specific age and stage of reproduction.live birth rate Pregnancy rate is the success rate for getting pregnant. It is the percentage of all attempts that leads to pregnancy, with attempts generally referring to menstrual cycles where insemination or any artificial equivalent is used, which may be simple ...

following assisted hatching compared with no assisted hatching.

References

Assisted reproductive technology Human reproduction {{Human-repro-stub