Table 2.

Association between maternal determinants and PTB subgroups

	EPTB (gestation < 28 week)
Variables	Adjusted OR	95% CI	P
History of preterm	4.4	2.2–8.5	0 < 0.001
Self reported health of mother	0.6	0.4–0.8	0.001
Marital status	5.1	1.9–13.7	0.001
	VPTB (28 ≤ gestation < 32 week)
Variables	Adjusted OR	95% CI	P
History of preterm	4.5	2.3–9.0	0.001
Primiparity	3.8	1.9–7.7	0.001
History of teen pregnancy	0.1	0.02–0.7	0.02
Self reported health of mother	0.7	0.5–0.9	0.02
Gestational diabet	5.2	1.7–16.3	0.005
	MLPB (32 ≤ gestation < 37 week)
Variables	Adjusted OR	95% CI	P
History of preterm	6.1	4.5–8.4	0 < 0.001
Pre-pregnancy weight	2.3	1.3–3.9	0.003
History of teen pregnancy	0.4	0.2–0.7	0.003

EPTB(gestation < 28 week):Extremely preterm birth

VPTB (28 ≤ gestation < 32 week):Very preterm birth

MLPB (32 ≤ gestation < 37 week):Moderate to late preterm birth