IVF/embryo transfer treatment involves development of multiple follicles, oocyte retrieval and embryo transfer after fertilization. Despite recent advances in ovarian stimulation, gamete handling, the method of assisted fertilization and improved culture conditions, the implantation potential of embryos has remained low for a long time. Therefore, multiple embryos are usually replaced to compensate for their low implantation potential, but this is associated with a high risk of multiple pregnancies. In order to avoid the risk of multiple pregnancies especially high order ones, patients are usually advised to have one or two embryos replaced in the stimulated cycle while excess good quality embryos are cryopreserved for transfer later. There is a high possibility of zona hardening during the freezing and thawing process. It has been suggested that immersion in cryoprotectants and temperature changes during the process of cryopreservation may affect the physicochemical characteristics of the zona pellucida (ZP) by hardening it, and consequently may impair the natural process of blastocyst hatching (Schalkolff et al., 1989; Caroll et al., 1990; Vicente et al., 1990; Ilmmesse et al., 2005; Zech et al., 2005).
Assisted hatching (AH) has been used to promote the embryo’s ability to undergo hatching following the cryopreservation procedure. In vitro studies with both mouse and human embryos have indicated that an artificial gap in the zona pellucida, i.e. assisted hatching (AH), significantly improves the hatching ability of blastocysts grown in vitro as compared with embryos without AH (De Vos and Van Steirteghem, 2000). Two meta-analyses (Edi-Osagie et al., 2003; Sallam et al., 2003) demonstrated that AH increased the implantation and pregnancy rates, especially in women with a poor prognosis, repeated failures and in older women.
LAH increases the implantation and pregnancy rates, especially in women with a poor prognosis, repeated failures and in older women.
Article Contributed by :
Dr. Uma Maheswari
M.B.B.S., D.G.O., Fellowship in Reproductive Medicine
We came across with a 32 years old patient who was married for 6 years. She had a regular menstrual cycles, normal HSG with 5 failed IUI cycles underwent ICSI, fresh transfer with one blastocyst – Grade 4AA did not result in a pregnancy. Subsequently, she underwent two frozen embryo transfer(two blastocysts of grade 4AA transferred each time) which did not result in pregnancy. She is a case of repeated implantation failure. Her Anti phospholoipid antibody screening was normal, parental karyotyping was normal, Endometrial TB PCR was normal. In the present FET cycle, laser assisted hatching was done for two embryos. This has worked out for her! She is pregnant now, single intrauterine gestational sac of 5 weeks gestation noted.