Table 3:

Cox proportional hazard models for time to return

	Unadjusted analysis				Adjusted analysis
Variable	B	HR	95 %CI for HR	P-Value	B	HR	95 %CI for HR	P-Value
No IVF insurance coverage^a	−0.65	0.52	0.43–0.64	<0.001^b	0.90	2.45	0.53 – 11.42	0.253
Age (years)	−0.02	0.98	0.96–1.003	0.09	0.23	1.26	1.15 – 1.43	<0.001
Race/Ethnicity^a
African American	−0.69	0.50	0.32–0.80	0.003	−0.81	0.44	0.28 – 0.71	<0.001
Other	−0.23	0.79	0.53–1.19	0.260	−0.15	0.95	0.57 – 1.30	0.472
No prior live birth^a	0.002	1.002	0.80–1.25	0.987
No embryos cryopreserved^a	−0.38	0.68	0.56–0.84	<0.001	2.44	11.49	1.93 – 68.40	0.007
Oocytes retrieved	0.02	1.02	1.001–1.03	0.036
Pregnancy loss after first IVF cycle^a	−0.40	0.68	0.52–0.89	0.005	−0.47	0.63	0.48 – 0.83	<0.001
Estimated income (in $10,000)	0.002	1.00	0.97–1.03	0.940
Distance to clinic (in 25 miles)	0.04	1.04	0.93–1.16	0.476
Interaction between no embryos cryopreserved and age^c					−0.09			0.002
Interaction between no IVF
insurance coverage and age^c	−0.05							0.042

Note:

HR, hazard ratio; CI, confidence interval.

Reference groups are as follows: for No IVF insurance coverage: IVF insurance coverage; for Race/Ethnicity: Non-Hispanic white; for No prior live birth: Prior live birth; for No embryos cryopreserved: Excess embryos cryopreserved; for Pregnancy loss during first IVF cycle: Did not become pregnant during first IVF cycle.

P-value <0.05 between the group and the reference group.

See Table 4 for interaction-specific HR.