NCT03833869.

Study name	The effect of assisted hatching on implantation rate in frozen blastocyst transfer ‐ a prospective randomized controlled study
Methods	Current study aims to assess effects of assisted hatching on implantation rate of frozen blastocysts Randomised, parallel assignment, open‐label
Participants	84 participants 18 to 39 years Female Inclusion criteria: in vitro fertilisation patients at investigators' institution intended to undergo transfer of frozen 5‐day embryo (blastocyst); 18 to 39 years old; first to third treatment cycle; previously had maximum of 4 embryos transferred Exclusion criteria: over 40 years old; congenital or acquired uterine malformations; hydrosalpinx; chronic autoimmune disease; embryo intended to undergo pre‐implantation genetic diagnosis
Interventions	Experimental: assisted hatching 5‐Day frozen embryos will undergo assisted hatching before embryo transfer No intervention: control 5‐Day frozen embryos will not undergo any additional procedures before embryo transfer Procedure: assisted hatching Controlled hatching of zona pellucida in the laboratory before embryo transfer
Outcomes	Primary outcome measure Implantation rate [time frame: 5 to 6 weeks following embryo transfer] • Number of gestational sacs demonstrated on ultrasound divided by number of embryos transferred (expressed as percentage) Secondary outcome measures Chemical pregnancy [time frame: 5 to 6 weeks following embryo transfer] • Increase and subsequent decrease in beta hCG levels with no evidence of gestational sac on ultrasound Early spontaneous abortion [time frame: up to 15 weeks from embryo transfer] • Spontaneous abortion of pregnancy during first trimester of pregnancy
Starting date	1 March 2019
Contact information	Hadas Ganer Herman, MD; hadassganer@yahoo.com Edith Wolfson Medical Center, H̱olon, Israel
Notes	Clinicaltrials.gov identifier: NCT03833869 https://clinicaltrials.gov/ct2/show/NCT03833869 Other study ID number: 0020‐19‐WOMC Date first received 7 February 2019