Randomization
Every participant in the study has a unique identification number (ID). Participants were assigned to the group using the random permuted block randomization employed by the SAS software, Version 9.4, of the SAS System for Windows (SAS Institute Inc., Cary, NC, USA) with a block size of 12. Computer-generated randomization allocated the participants to either pre-notification or no pre-notification group. Gender and twins together with triplets were considered as stratification factors. Twins (