Table 2. Univariate and multivariate Cox regression analysis of prognostic factors for live-birth in advanced age women.

Risk factors	Unadjusted HR (95%CI)	P	Adjusted HR* (95%CI)	P
Age
35-37yr	Reference		Reference
38-39yr	0.63(0.55, 0.71)	<0.001	0.67(0.59, 0.77)	<0.001
40-42yr	0.31(0.26, 0.38)	<0.001	0.40(0.33, 0.48)	<0.001
≥43yr	0.05(0.03 0.09)	<0.001	0.08(0.05, 0.14)	<0.001
Ovarian reserve
Non-POSEIDON	Reference		Reference
POSEIDON group 2	0.46(0.41, 0.51)	<0.001	0.51(0.46, 0.58)	<0.001
POSEIDON group 4	0.18(0.15, 0.22)	<0.001	0.26(0.21, 0.31)	<0.001
BMI(kg/m2)
<18.5	0.97(0.79, 1.20)	0.780	0.93(0.75, 1.15)	0.487
≥25	1.05(0.90,1.23)	0.512	1.14(0.97, 1.33)	0.109
18.5-24.9	Reference		Reference
Parity≥1	0.82(0.73, 0.93)	0.002	1.02(0.89, 1.17)	0.773
Type of infertility (primary vs. secondary)	0.89(0.80, 0.99)	0.030	1.01(0.89, 1.14)	0.923
Treatment protocol (IVF vs. ICSI)	0.97(0.87, 1.08)	0.552	0.93(0.81, 1.07)	0.293
Cause of infertility
Unexplained	1.26(0.67, 2.37)	0.474	1.19(0.63, 2.23)	0.597
Severe endometriosis	1.05(0.78, 1.42)	0.752	1.01(0.74, 1.36)	0.992
Pelvic and tubal factor	1.13(0.99, 1.30)	0.075	1.05(0.90, 1.21)	0.557
Ovulatory dysfunction	0.94(0.57, 1.55)	0.797	1.01(0.61, 1.68)	0.966
Male factor	1.30(1.11, 1.51)	0.001	1.20(1.02,1.42)	0.025
Combined	Reference		Reference

*adjusted for female age, ovarian reserve, female BMI, parity, type of infertility, cause of infertility and treatment protocol.

HR=hazard ratio; CI=confidence interval; BMI=body mass index.