Table 1.

Distribution of demographic characteristics and maternal risk factors for prematurity among mothers with term (controls) and mother with pre-term deliveries (cases)

Maternal characteristic	Controls N (%)	Cases N (%)	Statistical Significance†
Demographic
Age at childbirtha	28.8 (18.8–38.7)	30.7 (19.4–41.9)	< 0.001‡
Family status
Married	339/341 (98.3%)	319/341 (93.6%)
Divorced	0/341 (0%)	4/341 (1.2%)	0.001
Single	4/341 (1.2%)	18/341 (5.28%)	P trend: < 0.001
Education level
Primary	35/343 (10.2%)	36/341 (10.6%)
Secondary	107/343 (31.2%)	110/341 (32.3%)
Post-secondary	70/343 (20.4%)	73/341 (21.4%)	0.02
Tertiary	116/343 (33.8%)	87/341 (25.5%)
Post-graduate	15/343 (4.4%)	35/341 (10.3%)	P trend: 0.85
Working Conditions
Unemployed	77/307 (25.1%)	89/320 (27.8%)	0.44
Partner unemployed	64/338 (18.9%)`	54/321 (16.8%)	0.48
Manual labour	46/232 (19.8%)	76/228 (33.3%)	0.001
Prolonged standing at work	103/232(44.4%)	112/229 (48.9%)	0.33
Working > 8 h per day	27/232 (11.6%)	80/229 (34.9%)	< 0.001
Life-Style
Smoking before pregnancy	92/340 (27.1%)	97/339 (28.6%)	0.65
Smoking during pregnancy	35/341 (10.3%)	38/339 (11.2%)	0.69
Clinical
Additional weight gain during pregnancya	12.23 (0.3–23.7)	10.96 (3–24)	0.003‡
Body mass index
BMI < 20	56/334 (16.8%)	65/279 (23.3%)
20 < BMI < 25	166/334 (49.7%)	132/279 (47.3%)
25 < BMI < 30	66/334 (19.8%)	55/279 (19.7%)	0.23
30 < BMI < 35	31/334 (9.3%)	19/279 (6.8%)
BMI > 35	15/334 (4.5%)	8/279 (2.9%)	Ptrend: 0.04
Gestational diabetes	74/341 (21.7%)	44/338 (13.0%)	0.003
Clinically diagnosed depression	5/339 (1.5%)	12/339 (3.5%)	0.09
Stress during gestation	12/341 (3.5%)	64/337 (19.0%)	< 0.001

^aMean and 95% Confidence Interval

†Independent Sample T test ‡ Pearson Chi Square