Table 3. Factors associated with HIV infection among pregnant women initiating ANC in Tanzania mainland, (N = 38783).

Variable	Positive n (%)	cOR (95% CI)	aOR (95% CI)	p-value
Age group (years)
15–24	582 (3.3)	Ref	Ref
25–34	1246 (7.8)	2.6 (2.3–2.8)	2.2 (1.9–2.5)	<0.001
35–44	557 (11.7)	4.1 (3.5–4.7)	3.9 (3.2–4.6)	<0.001
45+	71 (20.1)	7.2 (4.4–11.7)	7.0 (4.4–11.1)	<0.001
Education level
None	353 (7.2)	1.6 (1.2–2.2)	2.3 (1.6–3.4)	<0.001
Primary	1599 (6.8)	1.5 (1.1–2)	1.9 (1.3–2.6)	<0.001
Secondary	447 (5.0)	1.1 (0.8–1.5)	1.2 (0.9–1.7)	0.227
Post-secondary	57 (4.7)	Ref	Ref
Marital status
Single	294 (10.4)	1.9 (1.6–2.3)	3.3 (2.7–4.0)	<0.001
Co-habiting	348 (6.9)	1.2 (1–1.5)	1.4 (1.2–1.7)	0.001
Divorced/separated	69 (22.4)	4.8 (3.2–7.2)	4.8 (3.2–7.1)	<0.001
Widowed	26 (23.0)	5 (3.2–7.7)	3.4 (2.2–5.4)	<0.001
Married	1719 (5.7)	Ref	Ref
Employment status
Employed	155 (7.7)	1.6 (1.2–2.2)	1.7 (1.1–2.4)	0.008
Housewife	1032 (5.4)	1.1 (0.8–1.5)	1.2 (0.9–1.7)	0.262
Self-employed	1131 (7.5)	1.6 (1.1–2.1)	1.6 (1.1–2.2)	0.012
Unemployed	138 (5.0)	Ref	Ref
Total number of previous pregnancies
0	271 (2.7)	Ref	Ref
1–2	1219 (7.1)	2.8 (2.4–3.2)	2.2 (1.9–2.6)	<0.001
3–4	763 (9.6)	3.9 (3.3–4.6)	2.2 (1.8–2.6)	<0.001
>4	203 (6.0)	2.3 (1.9–2.9)	1.1 (0.8–1.4)	0.479
Locality
Rural	296 (4.3)	Ref	Ref
Semi-urban	954 (7.3)	1.8 (1.3–2.4)	1.5 (1.0–2.2)	0.030
Urban	1206 (6.4)	1.5 (1.1–2.1)	1.5 (1.1–2.1)	0.012
Health facility level
Dispensary	335 (5.5)	Ref	Ref
Health Centre	1412 (5.9)	1.1 (0.8–1.5)	1.1 (0.8–1.4)	0.669
Hospital	709 (8.0)	1.5 (1.1–2.1)	1.4 (0.9–2.0)	0.099

ANC- Antenatal clinic, cOR- Crude Odds Ratio, aOR- Adjusted Odds Ratio, CI- Confidence interval