Ernest Hung Yu Ng1, Estella Yee Lan Lau2, William Shu Biu Yeung2, Tak Ming Cheung2, Oi Shan Tang2, Pak Chung Ho2. 1. Department of Obstetrics and Gynaecology, The University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China. Electronic address: nghye@hkucc.hku.hk. 2. Department of Obstetrics and Gynaecology, The University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China.
Abstract
OBJECTIVE: To compare the implantation and ongoing pregnancy rates of frozen-thawed embryo transfer (FET) using laser thinning with those of laser breaching of the zona pellucida (ZP). DESIGN: Double-blind randomized study. SETTING: A tertiary assisted reproduction unit. PATIENT(S): Infertile patients undergoing FET cycles. INTERVENTION(S): In the thinning group, more than a quarter of the ZP's outer half-diameter was removed by using a 1,480-nm noncontact laser, whereas a hole about 30 microm in size was created in the ZP in the breaching group. MAIN OUTCOME MEASURE(S): Implantation and ongoing pregnancy rates. RESULT(S): On the day of the FET, 180 patients were randomly divided into the thinning and breaching groups according to a computer-generated randomization list that was placed in sealed envelopes. The two groups were comparable in terms of demographic characteristics, ovarian response of the stimulated cycle, and quality of fresh and frozen-thawed embryos. The implantation and ongoing pregnancy rates of the thinning group were significantly higher than the corresponding rates of the breaching group but were similar to those of patients without ZP thinning or breaching. CONCLUSION(S): Laser ZP thinning is associated with significantly higher implantation and ongoing pregnancy rates in FET cycles compared with the case of laser ZP breaching.
RCT Entities:
OBJECTIVE: To compare the implantation and ongoing pregnancy rates of frozen-thawed embryo transfer (FET) using laser thinning with those of laser breaching of the zona pellucida (ZP). DESIGN: Double-blind randomized study. SETTING: A tertiary assisted reproduction unit. PATIENT(S): Infertile patients undergoing FET cycles. INTERVENTION(S): In the thinning group, more than a quarter of the ZP's outer half-diameter was removed by using a 1,480-nm noncontact laser, whereas a hole about 30 microm in size was created in the ZP in the breaching group. MAIN OUTCOME MEASURE(S): Implantation and ongoing pregnancy rates. RESULT(S): On the day of the FET, 180 patients were randomly divided into the thinning and breaching groups according to a computer-generated randomization list that was placed in sealed envelopes. The two groups were comparable in terms of demographic characteristics, ovarian response of the stimulated cycle, and quality of fresh and frozen-thawed embryos. The implantation and ongoing pregnancy rates of the thinning group were significantly higher than the corresponding rates of the breaching group but were similar to those of patients without ZP thinning or breaching. CONCLUSION(S): Laser ZP thinning is associated with significantly higher implantation and ongoing pregnancy rates in FET cycles compared with the case of laser ZP breaching.