TABLE 2.

Factors associated with the risk of planned CB

Factor	Group	Planned CB (n = 166)	Other modes (n = 2589)	ARR (95% CI)	P‐value
Maternal age	Up to 24 years	6 (2.8%)	207 (97.2%)	0.63 (0.26‐1.53)	0.306
	25‐29 years	26 (4.7%)	524 (95.3%)	1 (Ref)
	30‐34 years	58 (4.9%)	1132 (95.1%)	1.00 (0.63‐1.59)	0.984
	35‐39 years	52 (7.7%)	623 (92.3%)	1.42 (0.88‐2.30)	0.151
	≥40 years	24 (18.9%)	103 (81.1%)	2.77 (1.52‐5.05)	0.001
Prepregnancy BMI	Ideal weight	107 (6.0%)	1678 (94.0%)	1
	Overweight	31 (6.3%)	458 (93.7%)	1.00 (0.67‐1.50)	0.987
	Obese/very obese	16 (6.0%)	252 (94.0%)	1.04 (0.62‐1.77)	0.876
	Missing	12 (5.6%)	201 (94.4%)	1.01 (0.54‐1.89)	0.983
Treatment for infertility	No	124 (5.1%)	2328 (94.9%)	1 (Ref)
	Yes	41 (14.0%)	253 (86.0%)	2.03 (1.38‐2.99)	<0.001
Type of care	Public	77 (4.3%)	1718 (95.7%)	1 (Ref)
	Semiprivate	45 (7.8%)	529 (92.2%)	1.92 (1.33‐2.78)	0.001
	Private	44 (11.4%)	342 (88.6%)	2.78 (1.92‐4.04)	<0.001
Number of fetus(es)	Singleton gestation	154 (5.7%)	2546 (94.3%)	1 (Ref)
	Multiple gestation	12 (21.8%)	43 (78.2%)	2.81 (1.48‐5.35)	0.002
Cephalic presentation	Cephalic	91 (3.5%)	2528 (96.5%)	1 (Ref)
	Breech or other malpresentations	75 (55.2%)	61 (44.9%)	15.99 (11.77‐21.74)	<0.001
Gestational age at birth	Term	148 (5.7%)	2446 (94.3%)	1 (Ref)
	Preterm	18 (11.2%)	143 (88.8%)	1.17 (0.69‐2.00)	0.554

Note: Data were missing for treatment for infertility (n = 9). The model included prepregnancy factors (maternal age, prepregnancy BMI, and treatment for infertility. Preexisting medical conditions were not significantly associated with the risk of a planned CB in bivariable analysis, and hence were not included in the multivariable Poisson regression model. Prepregnancy BMI was not identified to be significantly associated with the risk of planned CB, but it was included in the model because of its clinical importance) and pregnancy factors (type of care, number of fetus(es), gestational age, and presentation of fetus at birth).

Abbreviations: ARR, adjusted risk ratio; CI, confidence interval.