Assisted hatching

Assisted hatching entails the opening or thinning of the zona pellucida before embryo transfer in order to improve the results of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). The technique can be performed mechanically, chemically or with a laser beam. A piezoelectric method has also been described. Meta-analyses of randomised trials have shown that assisted hatching increases the clinical pregnancy, implantation and on-going pregnancy rates in patients with poor prognosis for IVF and ICSI, particularly those with repeated implantation failure. The technique is not without risks, and has been associated with an increased incidence of monozygotic twinning. Nevertheless, it remains an invaluable tool in assisted reproductive technology.