Table 2 Clinical characteristics and secondary outcomes in the randomized cohort (by intention to treat), low and mid station VAD

 BMI (kg/m²)¹

24±4

24±4

0.48

  Missing

16 (5%)

9 (3%)

 Nulliparous

233 (79%)

205 (76%)

0.42

 Gest. length, days¹

283±9

282±8

0.25

 Age¹

31±5

32±5

0.63

 Height¹

164±7

164±7

0.68

 Failed vacuum extraction

25 (8%)

31 (11%)

0.26

 Time fully dilated to vacuum extraction, hours¹

3.1±1.5

2.9±1.5

0.08

 Time cx 3 cm – fully dilated, hours¹

8.8±5

8.9±5

0.76

 Subjective heavy extraction

53 (18%)

51 (19%)

0.83

  Missing

12 (4%)

8 (3%)

 Epidural

248 (84%)

223 (82%)

0.66

 Oxytocin

285 (96%)

260 (96%)

0.83

 Indication OFHR

94 (32%)

79 (29%)

0.52

  - Mid

156 (53%)

150 (55%)

0.56

  - Low

140 (47%)

121 (45%)

0.56

 Number of pulls, n³

2 (4-2)

2 (4-2)

0.67

  Missing

7 (2%)

7 (3%)

 Vacuum extraction duration, min³

6 (9-3)

5 (9-4)

0.61

 Position (OAP)

273 (92%)

237 (87%)

0.07

 Pop-off

23 (8%)

24 (9%)

0.65

 Pop-off ≥2

3 (1%)

5 (2%)

0.49

 Shoulder dystocia

4 (1%)

2 (0.7%)

0.69

 Birth weight, g¹

3570±490

3569±423

0.98

 NICU

25 (8%)

27 (10%)

0.56

 NICU, days²

2 (1-25)

2 (1-17)

0.99

 Gender

0.06

  - Male

187 (63%)

150 (55%)

  - Female

109 (37%)

131 (45%)

 pH<7.00

5 (2%)

2 (0.7%)

0.45

  Missing

30 (9%)

27 (11%)

 pH<7.10

37 (13%)

33 (12%)

1

  Missing

30 (9%)

27 (11%)

 APG<7 at 5 min

8 (3%)

10 (4%)

0.63

 Plexus injury

1 (0.3%)

3 (1%)

0.35

 Cefalohematoma

40 (14%)

28 (10%)

0.30

 Hyperbilirubinemia

27 (9%)

17 (6%)

0.21

 Fracture

1 (0.3%)

3 (1%)

0.35