Table 2. Factors of preterm labor/ectopic pregnancy by using Cox regression.

Events	Preterm labor				Ectopic pregnancy
Variables	Adjusted HR	95% CI	95% CI	P	Adjusted HR	95% CI	95% CI	P
PID
Without	Reference				Reference
With	1.864	1.482	2.062	<0.001	2.121	1.803	3.776.	0.003
Number of births
1	Reference				Reference
≥2	0.993	0.482	1.795	0.513	1.024	0.589	2.131	0.330
Age group (years)
12–19	Reference				Reference
20–29	0.607	0.462	0.797	<0.001	0.343	0.079	1.484	0.152
30–39	0.297	0.226	0.390	<0.001	0.192	0.044	0.842	0.029
40–49	0.025	0.017	0.036	<0.001	0.083	0.016	0.426	0.003
50–55	0.000	-	-	0.705	0.000	-	-	0.933
HTN	1.057	1.008	1.406	0.004	1.496	0.194	11.517	0.699
Heart disease	1.229	1.130	1.405	<0.001	1.792	1.108	5.831	<0.001
CKD	1.404	1.092	1.849	0.017	2.891	0.378	22.120	0.307
Level of care
Hospital center	1.275	1.069	1.626	0.010	1.883	1.669	2.126	<0.001
Regional hospital	1.194	1.026	2.576	0.038	1.475	1.324	1.644	<0.001
Local hospital	Reference				Reference

HR = hazard ratio, CI = confidence interval, adjusted HR: adjusted variables listed in the table

Adjusted variables: geographical area of residence, urbanization level of residence, monthly income, season, diabetes mellitus, hyperlipidemia, and obesity