Immediate versus delayed frozen embryo transfer in women following a failed IVF-ET attempt: a multicenter randomized controlled trial

Table 3 Relationship between the timing of initial FET after a fresh IVF-ET attempt failure and pregnancy outcomes in different models

Pregnancy outcomes	Timing of initial FET	Crude model ^a		Adjusted model I ^b		Adjusted model II ^c
Pregnancy outcomes	Timing of initial FET	OR (95% CI)	P value	OR (95% CI)	P value	OR (95% CI)	P value
Positive pregnancy	Immediate FET group	Reference		Reference		Reference
Positive pregnancy	Delayed FET group	1.09 (0.80to 1.48)	0.587	1.04 (0.75 to 1.44)	0.810	0.95 (0.67 to 1.35)	0.781
Clinical pregnancy	Immediate FET group	Reference		Reference		Reference
Clinical pregnancy	Delayed FET group	0.74 (0.54 to 1.02)	0.066	0.70 (0.50 to 0.97)	0.031	0.68 (0.47 to 0.97)	0.031
Ongoing pregnancy	Immediate FET group	Reference		Reference		Reference
Ongoing pregnancy	Delayed FET group	0.78 (0.55 to 1.05)	0.096	0.71 (0.51 to 0.99)	0.048	0.68 (0.47 to 0.99)	0.041
Live birth	Immediate FET group	Reference		Reference		Reference
Live birth	Delayed FET group	0.75 (0.54 to 1.04)	0.080	0.70 (0.50 to 0.98)	0.038	0.67 (0.46 to 0.96)	0.031

Abbreviation: AMH Anti-müllerian hormone, BMI Body mass index, FSH Follicle stimulating hormone, OR Odds ratio, CI Confidence interval, FET Frozen embryo transfer, IVF-ET In vitro fertilization-embryo transfer, AFC Antral follicle count, COS Controlled ovarian stimulation; Gn, gonadotropin
^a No adjustments for other covariates
^b Adjusted for female age (< 35 yrs., ≥ 35 yrs.), moderate/severe depression prior to FET (yes, no), and high stress level prior to FET (yes, no)
^c Adjusted for female age (< 35 yrs., ≥ 35 yrs.), AMH (< 1.2 ng/ml, ≥ 1.2 ng/ml), BMI (< 24 kg/m², ≥ 24 kg/m²), basic FSH (< 10 UI/L, ≥ 10 UI/L), AFC (< 10, ≥ 10), endometrial thickness before FET, No of oocytes retrieved (≤ 9, > 9), No of transferred frozen thawed embryos (single, double), method of fertilization (IVF, ICSI), moderate/severe depression prior to FET (yes, no), and high stress level prior to FET (yes, no)

ISSN: 1477-7827