Table 5.

Relationship between the time interval between two ovulation induction IUI trearment cycles and clinical pregnancy after adjusting for confounding factors

Variable	Control group	B value	OR value	OR 95% CI	P value
Time interval
Discontinuous	Continuous	−0.016	0.984	0.495 to 1.957	0.964
Male age (years)		−0.026	0.974	0.849 to 1.117	0.708
Female age (years)		0.016	1.016	0.876 to 1.179	0.831
Type of infertility
Secondary infertility	Primary infertility	1.07	2.917	1.421 to 5.988	0.004
Female BMI		0.059	1.061	0.972 to 1.159	0.186
Endometrial thickness (mm)		0.196	1.217	1.056 to 1.401	0.006
Semen volume before treatment (mL)		−0.224	0.799	0.615 to 1.039	0.095
Sperm density before treatment (×106 /mL)		−0.004	0.996	0.987 to 1.004	0.318
Percentage of forward motile sperm before treatment (%)		−0.005	0.995	0.97 to 1.021	0.73
Sperm density after treatment (×106 /mL)		0.004	1.004	0.995 to 1.013	0.419
Percentage of forward motile sperm after treatment (%)		0.041	1.042	0.937 to 1.157	0.448
Duration of infertility
2–5 years	≤2 years	0.298	1.347	0.668 to 2.715	0.405
＞5 years	≤2 years	−0.836	0.433	0.159 to 1.185	0.103
Endometrial classification, n (%)
B	A	−0.694	0.5	0.243 to 1.026	0.059
C	A	0.409	1.505	0.312 to 7.254	0.61
Infertility factors
Ovulation disorders	Cervical factors	1.091	2.978	0.585 to 15.175	0.189
Unexplained infertility	Cervical factors	0.143	1.153	0.205 to 6.475	0.871
Tubal problems	Cervical factors	0.568	1.765	0.285 to 10.939	0.541
Male factor	Cervical factors	1.224	3.4	0.504 to 22.941	0.209

Adjustment factors include: Female age, male age, infertility duration, infertility type, female BMI, endometrial classification, endometrial thickness, semen volume before treatment, sperm density before treatment, percentage of forward motile sperm before treatment, sperm density after treatment, percentage of forward motile sperm after treatment, infertility factors and the time interval between two ovulation induction IUI trearment cycles.

BMI, body mass index; IUI, intrauterine insemination.