Table 5 Selected variables with univariate and full model regression analysis, odds ratio and adjusted odds ratio of perineal tear grade 3 and 4 (OASI). Data for the whole group of women except when otherwise specified

Age at delivery^a

−0.009

0.4

–

–

Parity (higher)

−1.3

0.001

0.27**

0.2-0.4

−0.94

0.0001

0.39**

0.3-0.6

Dystocia treated with oxytocin

0.7

0.001

2.09**

1.5-3

− 0.07

0.7

1.07

0.8-1.5

Epidural

0.6

0.001

1.86**

1.4-2.5

0.11

0.42

1.12

0.8-1.5

Episiotomy

1.2

0.001

3.22**

1.8-5.6

0.16

0.62

1.18

0.7-2.1

OVD

2.1

0.001

7.9**

5.8-10.8

1.7

0.0001

5.3**

3.9-7.2

Communication

0.3

0.31

1.24

0.8-2.4

0.34

0.83

1.41

0.9-2.7

Visible perineum

−0.18

0.44

0.84

0.5-1.3

−0.06

0.862

0.95

0.6-1.5

Hand on fetal head

−1.2

0.001

0.3**

0.2-0.5

−0.78

0.001

0.46**

0.3-0.8

Perineal support

−0.4

0.01

0.65*

0.5-0.9

−0.78

0.0001

0.47**

0.4-0.7

Certification

0.51

0.07

1.67

0.97-2.9

0.07

0.2

1.47

0.9-2.6

All five elements ^b

−0.3

0.047

0.74*

0.6-0.99

−0.49

0.001

0.61**

0.5-0.8

Birth weight ^a

0.061

0.0001

–

–

Multiparous only:

Previous cesarean

2.3

0.001

10.3**

6-17.8

1.9

0.001

6.8**

4-12