Assisted hatching is an IVF technique in which the zona is treated prior to embryo transfer in order to weaken the wall of the embryo and thus improve the likelihood of successful hatching and embryo implantation.
The zona pellucida (egg shell) has a complex structure that envelopes the egg/embryo. In nature, about two days after an embryo reaches the uterus, the zona opens and all the embryonic cells hatch out, which then try to burrow into the endometrium to establish the implantation. This is known as hatching.
The inefficiency of human in vitro fertilization (IVF) is largely due to implantation failure. Possible causes of this failure of embryos to implant successfully include :
- Genetic abnormalities of embryos
- Sub-optimal physiological and morphological development of IVF embryos
- Impaired uterine receptivity
- Abnormalities of the zona pellucida -- the presence of a thick zona or zona hardening, which
- May be caused by the embryo cryopreservation procedure as observed in animal research studies. These seem to occur more often in those infertile patients with elevated maternal age and poor prognosis.
INDICATIONS FOR ASSISTED HATCHING
- Elevated maternal age
- Elevated follicle stimulating hormone (FSH) level
- Evidence of a thickened zona pellucida of the embryos in IVF
- Unexplained implantation failure after two or more -embryo transfers
Assisted hatching is generally performed on the third day of embryo culture. Briefly, the microscopic assisted hatching procedures was accomplished by blowing the chemical zona-drilling solution (an acidified buffer) very slowly and gently over the surface of the zona to create an opening in the zona. The zona-drilled embryos are then rinsed several times in fresh culture medium before returning them to standard culture conditions inside the IVF laboratory prior to the embryo transfer. We now perform laser assisted hatching wherever indicated.
With this latest technology and the expertise of our IVF staff, we have had great success with achieving pregnancies for many couples who may never have an opportunity for successful parenthood.
