Recurrent implantation failure might be identified after three unsuccessful IVF cycles or after the embryo transfer of 10 high-grade embryos. Multiple factors may lead to embryo implantation failure, for example, parental genetic translocations, abnormal uterine anatomy (septa, submucous myoma, or intrauterine adhesions), hydrosalpinx or insufficient culture conditions or embryo transfer technique.
Some clinicians have confirmed that local injury of the endometrium using a catheter or hysteroscopy can induce an inflammatory response that may facilitate the preparation for implantation. However, large assessments are needed before this can be warranted in routine clinical practice.
The artificial rupture of the zona pellucida, known as “assisted hatching”, is considered to improve implantation and clinical pregnancies. Recent assessments reported a significant improvement in clinical pregnancy when performed in fresh embryos transfer to women with recurrent implantation failure. However, these were unable to draw any conclusions regarding live birth or miscarriage rates. The only preimplantation genetic aneuploidy screening as an approach to improve recurrent implantation failure patients’ outcome demonstrated no factor on clinical pregnancy rates.
A few evidences have reported that congenital and acquired prothrombotic conditions are more widespread in women with recurrent implantation failure. Therefore, a potential advantageous effect of the administration of low-molecular-weight heparin (LMWH) and minidosage of aspirin on patients with thrombophilia and recurrent implantation failure has been thought.
Finally, another possible technique is to increase embryo culture to the Day 5 blastocyst stage, aiming to improve embryo selection and uterine receptivity. The outcomes are higher implantation, pregnancy rate and live birth rate per cycle when a blastocyst has been replaced.
To conclude, there is no single technique to improve live birth rates in patients with recurrent implantation failure. Consequently, a case-by-case trial is suggested assessing all possible etiologies and discussing the various available methods to enhance the chances of pregnancy.