The Study of Zona Hatching Effect on expansion of fertility rate in embryos with thick zona by laser beam

Nowadays, different techniques are used for increasing pregnancy rate in laboratories of in vitro fertilization (IVF). One of these techniques is laser assisted hatching (LAH) which help the embryo be separated from zona pellucida. Since there are contrast reports about the efficacy of LAH on pregnancy rate in embryo of thick zona, we decided to evaluate the correlation between zona pellucida thickness by LAH and increasing pregnancy rate in infertile patients under treatment of IVF at Mashhad Montaserieh Infertile Center. This case-control study was performed on 101 infertile couples (50 in case group and 51 in control group). Two groups were similar in terms of maternal age, number of oocytes, number of fertilized oocytes, and number of transferred embryos. Also, embryos with similar quality were used for both groups. Pregnancy rate was determined using β-HCG test and sonography. Data analyzing was performed by t-test, Chi-square, SPSS and Excel software (95% confidence coefficient). P value less than 0.05 considered significant. There was no significant relation between case and control groups in terms of maternal age, number of fertilized oocytes, number of aspirated oocytes, number and quality of transferred embryos (p=0.837). Pregnancy rate in case and control groups was 15.7%, 34%, respectively. Significant difference was observed between two groups in terms of pregnancy rate (p=0.33). Laser assisted hatching method on embryos of thick zona pellucida leads to increasing of pregnancy rate.Keywords: In vitro fertilization, Laser assisted hatching, Pregnancy rate, Zona pellucida thickness