Definition of ROM

Rate of CD

early ROM

Rate of CD

late ROM

p-Value

Modified Bishop score

All women (N = 279)

Nulliparous (N = 133)

Multiparous (N = 146)

<5

32% (16/50)

60% (12/20)

13.3% (4/30)

≥5

17.5% (40/229)

27.4% (17/229)

7.8% (9/116)

0.031

0.008

0.469

Cervical dilation

All women (N = 279)

Nulliparous (N = 133)

Multiparous (N = 146)

<4 cm

32.4% (12/37)

38.1% (8/21)

25% (4/16)

≥4 cm

18.2% (44/242)

31.3% (35/112)

6.9% (9/130)

0.049

0.613

0.038

Cervical effacement

All women (N = 279)

Nulliparous (N = 133)

Multiparous (N = 146)

<80%

33.3% (26/78)

62.1% (18/29)

16.3% (8/49)

≥80%

14.9% (30/201)

24% (25/104)

5.2% (5/97)

0.001

<0.0001

0.033