title: The impact of laser-assisted hatching on the outcome of frozen human embryo transfer cycles.
abstract: Biochemical modifications of zona pellucida (ZP) result in zona hardening. Zona hardening (ZH) is induced by several factors such as advancing maternal age, in vitro culture conditions and cryopreservation and adversely effects implantation. The objective of the clinical study was to determine whether or not laser-assisted hatching (LAH) applied on day 3 frozen embryos improves the outcome of frozen embryo transfer (FET) cycles in patients with recurrent implantation failure and/or advanced female age. In total, 413 patients of different ages with recurrent implantation failure (maximum three cycles) were involved into the study. Patients were allocated randomly into LAH and control groups. On the day of FET, after thawing and just before FET, the ZP was thinned using a laser system. In the control group no treatment was applied on frozen embryo before transfer. The main outcome measures were clinical pregnancy rate. Overall, the results indicate a tendency that LAH increased (P = 0.08) clinical pregnancy. However, for patients older than 37 years, LAH increased pregnancy rates significantly (P = 0.03). In the LAH and control groups, the age of patients and the number of transferred embryos influenced pregnancy rates (P = 0.01). For patients older than 37 years, no effect of number of transferred embryos was detected (P = 0.14). The incidence of multiple pregnancies also increased in the LAH group (P = 0.01). In conclusion, in older woman, to overcome the negative effect of zona hardening, LAH could be performed on frozen embryos as a routine strategy before FET in frozen cycles in order to increase the possibility of pregnancy formation.
authors.affiliation: Infertility and IVF Center of Buda,Szent Janos Hospital,Budapest 1125,Hungary.
authors.forename: Katalin
authors.initials: K
authors.lastname: Kanyo
authors.affiliation: Infertility and IVF Center of Buda,Szent Janos Hospital,Budapest 1125,Hungary.
authors.forename: Jozsef
authors.initials: J
authors.lastname: Zeke
authors.affiliation: Infertility and IVF Center of Buda,Szent Janos Hospital,Budapest 1125,Hungary.
authors.forename: Rita
authors.initials: R
authors.lastname: Kriston
authors.affiliation: Infertility and IVF Center of Buda,Szent Janos Hospital,Budapest 1125,Hungary.
authors.forename: Zoltan
authors.initials: Z
authors.lastname: Szücs
authors.affiliation: 1078 Budapest,Istvan u. 2.Hungary.
authors.forename: Sandor
authors.initials: S
authors.lastname: Cseh
authors.affiliation: Szent Istvan University Faculty of Veterinary Science,Budapest 1078,Hungary.
authors.forename: Bence
authors.initials: B
authors.lastname: Somoskoi
authors.affiliation: Infertility and IVF Center of Buda,Szent Janos Hospital,Budapest 1125,Hungary.
authors.forename: Janos
authors.initials: J
authors.lastname: Konc
mesh_terms: D000328:Adult; D015925:Cryopreservation / Q000379:methods*; D004624:Embryo Transfer / Q000379:methods*; D005260:Female; D006801:Humans; D007834:Lasers; D008423:Maternal Age; D011247:Pregnancy; D018873:Pregnancy Rate; D011272:Pregnancy, Multiple; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods; D016896:Treatment Outcome
keywords: Age of patients; Clinical outcome of laser-assisted hatching; Frozen embryo transfer cycle; Laser-assisted hatching; Slow freezing of embryos