Duration of second stage of labor and instrumental delivery as risk factors for severe perineal lacerations: population-based study

Table 2 Risk of severe perineal lacerations among nulliparous by duration of second stage of labor

Time^c			Severe perineal lacerations^a
			Crude		Adjusted^b
	N	%	OR	95% CI	aOR	95% CI
0–< 1 h	16972	5.3	1.00	Ref	1.00	Ref
1–< 2 h	15238	7.3	1.40	1.28–1.54	1.25	1.13–1.38
2–< 3 h	9424	9.0	1.76	1.59–1.94	1.42	1.28–1.58
3–< 4 h	6217	10.5	2.09	1.88–2.32	1.45	1.29–1.64
≥4 h	4368	12.1	2.46	2.20–2.76	1.41	1.24–1.61

^aPerineal lacerations third and fourth degree.^bAdjusted for maternal age, BMI, maternal height, parental cohabitation, smoking, epidural analgesia, oxytocin augmentation, induction of labor, gestational age, episiotomy, occiput posterior position, head circumference, birthweight more than 4500 g and mode of delivery
^cTime from fully dilated cervix to birth

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