Table 3.

Odds ratio for independent variables in multivariate logistic regression analysis.

Variables	OR (95% CI)	p
Maternal age ⩾ 35 y.o.	1.00 (0.59–1.70)	0.994
Gestational age < 37 wg	1.67 (1.11–2.54)	0.015
Primigravidity	1.31 (0.63–2.74)	0.456
Pre-pregnancy BMI (underweight)	0.42 (0.22–0.78)	0.007
Pre-pregnancy BMI (overweight)	0.87 (0.49–1.55)	0.641
Pre-pregnancy BMI (obese)	0.93 (0.59–1.70)	0.781
Excessive weight gain	1.09 (0.54–2.20)	0.798
Presence chronic disease	1.18 (0.72–1.94)	0.512
No history of vaginal delivery	2.14 (1.06–4.34)	0.034
Previous uterine surgery	9.75 (4.64–20.51)	< 0.001
Obstetrical complications	5.67 (3.54–9.09)	< 0.001
Birth weight ⩾ 3500 g	4.25 (2.13–8.49)	< 0.001
Non-cephalic presentation	2.75 (1.53–4.95)	0.001

OR: odds ratio; CI: confidence interval; wg: weeks of gestation; BMI: body mass index.