Table 1 Demographics and obstetrics characteristics of multiparous women (n = 7109)

 First stage (hour) ^a

6.2

3.6–10.0

   < 6 h

3398

47.8

  6–11.9 h

2512

35.3

  12–17.9 h

820

11.5

  18–23.9 h

228

3.2

   ≥ 24 h

151

2.1

 Second stage (hour) ^a

0.3

0.2–0.7

   < 1 h

5791

81.5

  1–1.9 h

776

10.9

  2–2.9 h

278

3.9

  3–3.9 h

129

1.8

   ≥ 4 h

135

1.9

 Total stage (hour) ^a

6.9

4.1–10.7

   < 12 h

5717

80.4

  12–23.9 h

1208

17.0

   ≥ 24 h

184

2.6

Gestational age (weeks) ^a

39.6

39.0–40.3

Maternal age (years) ^a

33.0

30.0–36.0

Maternal Height (cm) ^a

162.6

160.0–167.6

Gestational weight gain (kg) ^a

14.0

10.0–17.0

Maternal BMI (kg/m²) ^a

29.4

26.6–32.6

Gravidity^a

3.0

2.0–4.0

Parity^a

2.0

2.0–3.0

Baby weight (g) ^a

3459

3175–3750

Baby height (cm) ^a

50.8

48.3–52.1

 Non-Hispanic White

4671

65.7

 Non-Hispanic Black

558

7.9

 Hispanic

273

3.8

 Asian or Pacific Islanders

737

10.4

 Other or Unknown

870

12.2

Epidural analgesia

5423

76.3

Induction

1647

23.2

Oxytocin

1975

27.8