1
Published 2011
RCOG Press at the Royal College of Obstetricians and Gynaecologists

2
Published 2013
Royal College of Obstetricians and Gynaecologists

3
Published 2017
National Institute for Health and Care Excellence

4
by Welsh, Andrew
Published 2010
Royal College of Obstetricians and Gynaecologists

5
Published 2017
National Institute for Health and Care Excellence

7
Published 2013
Royal College of Obstetricians and Gynaecologists

9
Published 2017
National Institute for Health and Care Excellence

10
Published 2018
National Institute for Health and Care Excellence

12
Published 2017
National Institute for Health and Care Excellence

13
Published 2017
National Institute for Health and Care Excellence

14
Published 2017
National Institute for Health and Care Excellence

15
Published 2018
National Institute for Health and Care Excellence