2.6. Randomization, allocation, and blinding
Randomization and allocation will start on day 2 or 3 of the previous menstrual cycle before IVF. Eligible women will be stratified by AFC (<5 or ≥5) and randomized within the 2 strata. All participants will be randomly assigned to either the EZTG group or the placebo group in a 1:1 ratio. Randomization will be completed by software (R 4.0.0, R Foundation for Statistical Computing, Vienna, Austria), and different-sized block groups of 2, 4, 6 will be applied. Random number tables will be provided by statistical professionals not involved in the rest of the study and the number will be sealed into brown envelopes. Then the group allocation will be accomplished by opening envelopes sequentially in the order in which patients were recruited.A double-blind study design will be applied to enhance the quality of the study evidence. Both medications (EZTG granules and placebo) will be prepared in a manner that they will appear similar in appearance, flavor, and smell. Clinicians and patients will not be able to distinguish the difference between groups. The outcome assessment and data analysis will also be conducted in blinding. When the clinical trial is over, the final blind-break process is performed by authorized researchers.