Efficacy and safety of Dingkun pill for female infertility patients with low prognosis undergoing in vitro fertilization-embryo transfer: study protocol for a multicenter, double-blind, randomized, placebo-controlled trial

Table 1 Schedule of the study process (SPIRIT Figure)

	Study period
	Enrollment	Allocation	Post allocation
Timepoint*	1st visit	0 week	1–6 weeks	7–12 weeks	4–6 months
Enrollment:
Eligibility screen	√
Informed consent	√
Allocation by TCM team		√
Interventions:
DKP treatment			√
Placebo treatment			√
Assessments:
Basic ovarian reserve test (AFC, bFSH, AMH, etc.)			√
Laboratory index measurement (oocyte, zygote, embryo, etc.)				√
Pelvic ultrasound evaluation (endometrium thickness and classification)				√
IVF pregnancy outcome					√
Liver and renal function assessment				√	√

ISSN: 1745-6215