Table 3A.

Risk factors for study outcomes, multivariable estimates (GA at enrolment ≤20 weeks)

Characteristics	Study outcomes
	Caesarean sections n=11 628, 24% RR (95% CI)†	Pregnancy-related maternal complications n=6762, 14% RR (95% CI)†	Stillbirths n=1104, 2.3% RR (95% CI)†	Neonatal deaths (within 28 days of birth) n=963, 2.0% RR (95% CI)†	Low birth weight (<2500 g) n=8378, 18% RR (95% CI)†
Mother’s age (years)
<20	0.83†* (0.73 to 0.95)	0.83* (0.72 to to 0.97)	0.73 (0.47 to 1.12)	1.23 (0.87 to 1.75)	1 (0.88 to –1.15)
20–29	Ref	Ref	Ref	Ref	Ref
>29	1.56** (1.44 to 1.68)	1.37** (1.22 to 1.53)	1.45* (1.13–1.86)	1.37* (1.03 to 1.80)	1.27** (1.15 to 1.40)
Mother’s education (grades)
Primary or less (≤4)	0.50** (0.46 to 0.54)	0.76** (0.70 to 0.83)	1.68** (1.39 to 2.04)	1.53** (1.24 to 1.87)	1.17** (1.08 to 1.25)
Secondary (5–10)	0.70** (0.67 to 0.73)	0.90** (0.85 to 0.94)	1.40** (1.21 to 1.61)	1.30** (1.12 to 1.52)	1.15** (1.09 to 1.21)
University (>10)	Ref	Ref	Ref	Ref	Ref
Parity
Nulliparous	1.33** (1.28 to 1.39)	2.00** (1.86 to 2.15)	1.32** (1.17 to 1.50)	1.57** (1.38 to 1.80)	1.38** (1.31 to 1.44)
1–2	Ref	Ref	Ref	Ref	Ref
>2	0.49** (0.40 to 0.60)	0.80* (0.63 to 1.00)	1.50* (1.06 to 2.13)	1.62* (1.10 to 2.37)	0.99 (0.85 to 1.17)
Anaemia (g/dL)
Severe/moderate (<10)	0.89** (0.84 to 0.95)	0.90* (0.83 to 0.98)	1.16 (0.92 to 1.46)	1.37* (1.06 to 1.77)	1.24** (1.14 to 1.35)
Mild (10–11)	0.91* (0.86 to 0.97)	0.92* (0.85 to 0.99)	1.12 (0.88 to 1.41)	1.16 (0.90 to 1.50)	1.09 (1.00 to 1.18)
Normal (≥11)	Ref	Ref	Ref	Ref	Ref
Body mass index (kg/m2)
Underweight (<18.5)	0.81** (0.77 to to 0.84)	0.83** (0.79 to 0.88)	1.08 (0.96 to 1.22)	1.09 (0.96 to 1.24)	1.18** (1.13 to 1.23)
Normal (18.5–24.9)	Ref	Ref	Ref	Ref	Ref
Overweight or obese (≥25)	1.64** (1.51 to 1.78)	1.44** (1.28 to 1.61)	1.19 (0.84 to 1.67)	1.25 (0.87 to 1.79)	0.91 (0.79 to 1.04)

*P<0.05, **p<0.001.

†Obtained by multivariable GEE regression models for each outcome, separately.

GA, gestational age; GEE, generalised estimating equations.