Table 1.

Schedule of the study process (SPIRIT Figure).

	Study Period
	Enrollment	Allocation	Post allocation
Time point*	1st visit	2nd visit	3rd visit	Pregnancy visit	Follow-up visit
Preconception counselling	√	√	√	√	√
Eligibility screen	√
Informed consent	√
Questionnaire	√	√
Laboratory index measurement (oocyte, zygote, embryo, etc.)	√
Serological test for pregnancy		√	√	√
Allocation (immediate FET or delayed FET)		√	√
Menstrual cycle records			√
Transvaginal ultrasound for pregnancy outcomes			√	√	√
Perinatal and neonatal outcomes records				√	√