Association between interpregnancy interval and maternal and neonatal adverse outcomes in women with a cesarean delivery: a population-based study

Table 2 Association between interpregnancy interval (IPI) and the risk of repeat cesarean delivery

Cesarean delivery	Interpregnancy interval
	≤ 11 month		12–17 month		18–23 month	24–35 month		36–59 month		≥ 60 month
	OR (95% CI)	P	OR (95% CI)	P	OR (95% CI)	OR (95% CI)	P	OR (95% CI)	P	OR (95% CI)	P
Total population	1.55 (1.44–1.66)	< 0.001	1.38 (1.33–1.43)	< 0.001	1.00 [Ref]	0.98 (0.96–1.01)	0.159	1.12 (1.10–1.15)	< 0.001	1.19 (1.16–1.22)	< 0.001
Age group
< 35	1.47 (1.36–1.58)	< 0.001	1.34 (1.29–1.40)	< 0.001	1.00 [Ref]	1.01 (0.98–1.04)	0.431	1.17 (1.14–1.21)	< 0.001	1.28 (1.24–1.31)	< 0.001
≥ 35	1.77 (1.34–2.33)	< 0.001	1.37 (1.24–1.53)	< 0.001	1.00 [Ref]	0.92 (0.86–0.98)	0.008	1.02 (0.96–1.09)	0.460	1.23 (1.15–1.31)	< 0.001
Previous preterm births group
No	1.56 (1.44–1.68)	< 0.001	1.38 (1.33–1.44)	< 0.001	1.00 [Ref]	0.98 (0.96–1.01)	0.162	1.12 (1.09–1.15)	< 0.001	1.20 (1.16–1.23)	< 0.001
Yes	1.52 (1.20–1.92)	< 0.001	1.29 (1.12–1.48)	< 0.001	1.00 [Ref]	0.98 (0.88–1.09)	0.754	1.14 (1.03–1.27)	0.014	1.12 (1.01–1.25)	0.035

OR odds ratio, CI confidence interval, Ref reference; OR shows the results of multivariate logistic regression analysis after adjusting for age (unadjusted in age group analysis), race, education level, marital status, weight gain, smoking before pregnancy, smoking during pregnancy, prenatal care, pre-pregnancy BMI, pre-pregnancy diabetes, gestational diabetes, pre-pregnancy hypertension, gestation hypertension, eclampsia, assisted reproductive treatment, gestational age, clinical chorioamnionitis or maternal fever during labor, and previous preterm birth (unadjusted in previous preterm births group analysis)

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