Effect Of Laser-assisted Hatching On Pregnancy Outcomes Of Vitrified-warmed Blastocyst Transfer Cycles

BackgroundAs one of the assisted embryo hatching methods,laser-assisted hatching(LAH)has been used widely,especially in vitrified-warmed blastocyst transfer(VBT).However,it is invasive to embryos and few studies based on a large sample size have focus on the effect on live birth and birth defects.MethodsTo investigate the impact of LAH on the pregnancy outcomes,we conducted a retrospective study including 4039 VBT cycles in the Center for Reproductive Medicine,Shandong University from November 2014 to December 2015(LAH group,n=1932;non-LAH group,n=2107).Statistical analyses were conducted using the t-test and chi-square test.The primary outcomes were the live birth and birth defect rates,and subgroup analysis was performed based on the patient’s age,endometrial thickness,fertilization method,developmental speed and Gardner’s score of blastocysts.Results1.There was an increased live birth rate(48.81%vs.45.51%;P=0.036;OR,1.141;95%CI,1.009-1.292)with comparable birth defect rates(P>0.05)in the LAH group than those of the non-LAH group.2.For the patients≥35 years old,patients with endometrial thickness≥0.9 cm,IVF blastocysts,Day 6 blastocysts,or blastocysts with well-developed trophoblasts,LAH was relevant to a higher live birth rate(P<0.05)with comparable birth defect rates(P>0.05).ConclusionLAH didn’t increase birth defect rates and could be performed selectively on VBT.Patients over 35 years of age,with a good endometrium,or blastocysts from IVF,D6 blastocysts,or with well-developed trophoblasts,may benefit from LAH.