Duration (hours)

Primiparous

Multiparous

Total

p

N (%)

N (%)

N (%)

6 - 7

8 (2.2)

63 (17.7)

71 (19.9)

<0.0001^*

8 - 9

194 (54.3)

73 (20.5)

267 (74.8)

<0.0001^*

10 - 11

17 (4.7)

2 (0.6)

19 (5.3)

0.06^*

Overall duration

9.5 ± 1.8

8.4 ± 1.7

9.1 ± 1.2

<0.0001^**