Table 2. Binary and multivariable logistic analysis of predictors of preterm birth cases (n = 72) and controls (n = 286) in selected hospitals of Wollega zones, 2017/18.

Variables	Controln[%],	Cases n [%]	COR[95% CI]	AOR[95% CI]
	[n = 286]	[n = 72]
Number of ANC
None	27[62.8]	16[37.2]	4.56[2.14–9.71] *	3.18[1.37–7.38]*
1–2	82[71.3]	33[28.7]	3.09[1.71–5.6] *	2.27[1.18–4.35]*
3–4	177[88.5]	23[11.5]	1	1
History of Abortion
Yes	39[67.2]	19[32.8]	2.27[1.22–4.24]*	1.49[0.68–3.28]
No	247[82.3]	53[17.7]	1	1
Sex of the Newborn
Male	135[74.6]	46[25.4]	1.98[1.16–3.37]*	1.72[0.94–3.27]
Female	151[85.3]	26[14.7]	1	1
ANC Follow up
Yes	259[82.2]	56[17.8]	1	1
No	27[62.8]	16[37.2]	2.74[1.38–5.42]*	2.43[0.96–6.18]
Iron Supplementation
Not taken	41[81.2]	26[38.8]	4.06[1.41–11.75]*	2.30[0.66–8.03]
< = 3month	213[83.9]	41[16.1]	1.23[0.45–3.35]	1.12[0.36–3.48]
>3month	32[86.5]	5[13.5]	1	1
Outcome of the previous delivery
Prim	57[80.3]	14[19.7]	1	1
Term alive	194[85.1]	34[14.9]	0.71[0.36–1.42]	0.75[0.37–1.52]
Term stillbirth	20[69.0]	9[31.0]	1.83[0.69–4.88]	1.31[0.49–3.96]
Preterm	4[33.3]	8[66.7]	8.14[2.14–30.94]*	5.19[1.29–20.88]*
Abortion	11[61.1]	7[38.9]	2.59[0.85–7.89]	1.83[0.56–6.00]
IPI
Prim	48[87.3]	12.7[12.7]	O.74[0.21–1.84]	0.79[0.30–2.07]
<18monts	24[47.1]	27[52.9]	5.68[2.28–11.60]*	4.41[2.05–9.47]
18-23months	103[86.6]	16[13.4]	0.78[0.39–1.57]	1.02[0.49–2.15]
>23months	111[83.5]	22[16.5]	1	1
RTI
Yes	13[56.5]	10[43.5]	3.39[1.42–8.07]*	2.54[1.02–6.32]*
No	273[81.5]	62[18.5]	1	1
Faced obstetric complication**
Yes	82[64.6]	45[35.4]	4.15[2.41–7.13]	2.48[1.31–4.71]
No	204[88.3]	27[11.7]	1	1
Anxiety during pregnancy
Yes	15[62.5]	9[37.5]	2.58[1.08–6.17] *	1.86[0.63–5.50]
No	271[81.1]	63[18.9]	1	1

1Reference

*Significant association at P value <0.05

**Face obstetric complication:APH,Passage of liquor,PIH,GDM, Oligohydramnious and Polyhydramnious.