Table 3.

Association between patient and treatment characteristics and the likelihood of livebirth from four regression models (n = 2318 couples, 3913 IVF cycles).

Covariate	First cycle onlya Adjusted OR (95% CI)b	Discrete survivalc Adjusted OR (95% CI)b	GEEd Adjusted OR (95% CI)b	Mixed effectse Adjusted OR (95% CI)b
Previous livebirth
Nof	1.00	1.00	1.00	1.00
Yes	1.39 (1.10–1.75)	1.27 (1.06–1.52)	1.29 (1.07–1.56)	1.34 (1.04–1.74)
Woman’s age (years)
<35f	1.00	1.00	1.00	1.00
35–37	0.91 (0.71–1.16)	0.93 (0.77–1.12)	0.94 (0.77–1.14)	0.94 (0.76–1.16)
38–40	0.53 (0.40–0.71)	0.59 (0.47–0.72)	0.58 (0.47–0.72)	0.60 (0.40–0.82)
>40	0.21 (0.13–0.33)	0.21 (0.15–0.29)	0.21 (0.15–0.29)	0.19 (0.08–0.44)
Primary Diagnosis
Idiopathic f	1.00	1.00	1.00	1.00
Male	1.18 (0.88–1.57)	1.06 (0.86–1.31)	1.05 (0.85–1.31)	1.10 (0.86–1.40)
Female	0.91 (0.71–1.62)	0.93 (0.77–1.13)	0.92 (0.76–1.12)	0.93 (0.75–1.15)
Gonadotropin dose per 10 ampules	0.84 (0.77–0.91)	0.88 (0.84–0.93)	0.88 (0.84–0.92)	0.85 (0.77–0.93)
Down-regulation
No f	1.00	1.00	1.00	1.00
Yes	1.29 (0.97–1.72)	1.22 (1.00–1.48)	1.26 (1.04–1.52)	1.32 (1.02–1.71)
Intracytoplasmic sperm injection	0.79 (0.60–1.04)	0.94 (0.78–1.14)	0.94 (0.78–1.13)	0.86 (0.69–1.08)
No. Embryos transferred	1.30 (1.17–1.43)	1.24 (1.16–1.32)	1.24 (1.16–1.31)	1.22 (1.08–1.38)
Cycle # (Cox only)
Cycle 1 f		1.00
Cycle 2		0.86 (0.72–1.03)
Cycle 3		0.67 (0.52–0.87)
Cycle 4		0.69 (0.47–1.00)
Cycle 5		0.53 (0.29–0.98)
Cycle 6		0.08 (0.01–0.59)

^aMultivariate logistic regression using first-cycle data only (n = 2092 couples, 2092 cycles).

^bAll models were also adjusted for clinic site and study enrollment period.

^cDiscrete survival (Cox proportional odds model) fit using Proc Logistic, including cycle number as a class variable.

^dGeneralized estimating equations, using empirical estimates for standard errors and exchangeable working correlation, fit using Proc Genmod.

^eMixed effects model, using the logit link and Gaussian random intercept, fit using Proc NL Mixed.

^fReference category.