. 2016 Nov 16;355:i5735. doi: 10.1136/bmj.i5735

Table 3.

Effect and importance (in decreasing order) of each predictor on live birth over multiple complete cycles of in vitro fertilisation (IVF) adjusted for patient characteristics and treatment information at first complete cycle (post-treatment model)

Predictors	Odds ratio (95% CI)	P value	Adequacy
Intercept		<0.001
Complete cycle No:
1 (Reference)	1
2	0.82 (0.80 to 0.85)	<0.001
3	0.70 (0.67 to 0.73)	<0.001
4	0.60 (0.56 to 0.65)	<0.001
5	0.51 (0.44 to 0.58)	<0.001
6	0.46 (0.37 to 0.58)	<0.001
Patient characteristics
Woman’s age to 31 v 37 years*	1.53 (1.49 to 1.58.)	<0.001	0.435
Duration to 3 v 6 years	1.06 (1.05 to 1.08)	<0.001	0.036
Year first complete cycle started to 2006 v 2001*	1.29 (1.26 to 1.32)	<0.001	0.018
Tubal infertility to yes v no	0.80 (0.78 to 0.83)	<0.001	0.007
Previous pregnancy in couple to no v yes	0.95 (0.93 to 0.98)	<0.001	0.0001
Treatment information at first complete cycle
Cryopreservation of embryos to yes v no	1.91 (1.86 to 1.96)	<0.001	0.387
No of eggs collected to 13 v 5*	1.29 (1.27 to 1.32)	<0.001	0.378
Stage of embryos transferred:		<0.001	0.123
Double cleavage	1
No embryos transferred	0.34 (0.32 to 0.36)	<0.001
Single cleavage	0.57 (0.54 to 0.60)	<0.001
Single blastocyst	1.07 (0.93 to 1.24)	0.35
Double blastocyst	1.79 (1.67 to 1.91)	<0.001
Triple cleavage	1.02 (0.98 to 1.07)	0.36
Triple blastocyst	1.58 (1.15 to 2.14)	0.004
Treatment type to ICSI v IVF	0.91 (0.89 to 0.93)	<0.001	0.002

ICSI=intracytoplasmic sperm injection.

*Interquartile odds ratio was calculated to aid interpretation of continuous predictors of age, duration of infertility, year first complete cycle started, and eggs collected. It is defined as the ratio of the odds of a live birth for the 75th centile and the odds of a live birth for the 25 centile of the predictor.

Nagelkerke’s R² (amount of explained variation in model)=14.7%; Tjur’s coefficient of discrimination=510.3%.