Table 3. Maternal health during pregnancy and risk of preterm birth.

	Preterm group		Control group		P	OR	95%CI
	n	%	n	%
Pre-pregnancy BMI (kg/m2)
<18.5	180	13.9	202	15.0	0.956	0.994	0.791–1.248
18.5–24.9	858	66.4	928	68.8		1.000
25–29.9	227	17.6	206	15.3	0.124	1.192	0.953–1.492
≥30.0	28	2.0	12	0.9	0.005	2.946	1.377–6.302
Balanced diet
No	557	40.8	419	30.5		1.000
Yes	809	59.2	956	69.5	0.000	0.560	0.466–0.672
Stressful life event
No	1288	96.6	1352	99.2		1.000
Yes	46	3.4	11	0.8	0.000	4.400	2.116–8.743
Home or office decoration
No	1315	94.5	1339	96.3		1.000
Yes	76	5.5	52	3.7	0.006	1.960	1.211–3.173
Sex
No	695	50.0	771	55.4		1.000
Yes	696	50.0	620	44.6	0.000	1.451	1.189–1.771
Prenatal care
No	116	8.3	31	2.2		1.000
Yes	1275	91.7	1360	97.8	0.000	0.227	0.147–0.351