Group A

Group B

Primiparous

Multiparous

Primiparous

Multiparous

Study*

Control

Study*

Control

Study*

Control

Study*

Control

n = 240

n = 3781

n = 375

n = 1798

n = 143

n = 557

n = 160

n = 278

Ma ± SD

28.3 ± 5.1

Ma ± SD

30.6 ± 4.1

Ma ± SD

30.6 ± 4.1

Ma ± SD

32.4 ± 4.3

Ma ± SD

30.3 ± 4.6

Ma ± SD

31.7 ± 3.9

Ma ± SD

32.8 ± 5.0

Ma ± SD

33.4 ±4.3