Table 5. Bivariate and multivariate analysis of factors associated with physical activity status among pregnant women attending antenatal care at Hanoi Obstetrics & Gynecology Hospital (n=234)

Variables	Bivariate analysis		Multivariate analysis
	p-value	OR (95% CI)	p-value	OR (95% CI)
Age group
18–24		(ref)		(ref)
25–34	0.18	0.58 (0.26–1.28)	0.03	0.33 (0.12–0.93)
≥35	0.03	0.30 (0.10–0.90)	0.009	0.16 (0.04–0.63)
Level of education
Non-formal education		(ref)		(ref)
Primary and secondary school (1–9 grades)	0.21	3.19 (0.52–19.64)	0.20	3.77 (0.50–28.59)
High school (10–12 grades)	0.57	1.63 (0.30–8.90)	0.65	1.56 (0.24–10.25)
College/university and above level	0.42	1.89 (0.41–8.69)	0.84	1.21 (0.18–8.04)
Marital status
Not married		(ref)		(ref)
Married/living with partner	0.34	2.74 (0.34–21.96)	0.21	4.21 (0.45–39.60)
Occupational (employment) status
Mental work		(ref)		(ref)
Manual work	0.88	1.08 (0.42–2.75)	0.77	0.80 (0.19–3.41)
Other	0.75	0.89 (0.43–1.85)	0.31	0.53 (0.16–1.78)
Stage of pregnancy
First trimester (≤13 weeks)		(ref)		(ref)
Second trimester (14–27)	0.24	2.26 (0.58–8.75)	0.52	1.62 (0.38–7.03)
Third trimester (≥28 weeks)	0.13	2.61 (0.74–9.15)	0.21	2.35 (0.61–9.02)
Parity
≥1 child		(ref)		(ref)
0 child	0.06	0.54 (0.28–1.04)	0.61	0.81 (0.37–1.79)
Symptoms of discomfort
No		(ref)		(ref)
Yes	0.31	0.69 (0.34–1.41)	0.56	0.77 (0.32–1.87)
A habit of exercise before pregnancy
No exercise		(ref)		(ref)
Less than once a week	0.27	1.68 (0.67–4.18)	0.25	1.87 (0.64–5.47)
1–4 times/week	0.01	2.67 (1.25–5.74)	0.01	3.03 (1.21–7.62)
≥5 times/week	0.03	3.46 (1.11–10.74)	0.04	3.59 (1.05–12.24)
Pre-gravid BMI
Underweight: <18.5 kg/m2		(ref)		(ref)
Normal: 18.5–24.99 kg/m2	0.27	1.65 (0.68–3.98)	0.10	2.33 (0.85–6.39)
Overweight: 25–29.99 kg/m2	0.72	1.32 (0.30–5.85)	0.35	2.17 (0.43–10.98)
Obesity: ≥30 kg/m2	1.000	-	1.000	-
History of miscarriage/abortion
No		(ref)		(ref)
Yes	0.52	0.87 (0.39–1.95)	0.89	1.07 (0.41–2.82)
Exercise advice from a medical professional
No		(ref)		(ref)
Yes	0.52	0.79 (0.42–1.49)	0.08	0.51 (0.24–1.09)
Fitness central nearby the living place
No		(ref)		(ref)
Yes	0.1	1.87 (0.88–4.00)	0.03	2.51 (1.07–5.89)

CI, confidence interval; OR, odds ratio; BMI, body mass index.