Quality appraisal of studies
| RCTs* | Neu et al,35 2014 | Wiberg and Wiberg,45 1999 | Hayden and Mullinger,33 2006 | Miller et al,34 2012 | Olafsdottir et al,36 2001 | Browning and Miller,32 2008 | Herzaft-Le Roy et al,38 2017 |
| 1. Sequence generation | L | L | L | L | U | L | L |
| 2. Allocation concealment | L | U | U | L | L | U | L |
| 3. Blinding of parents | L | H | H | L | L | L | L |
| 4. Blinding of outcome assessors | L | L | H | L | L | L | L |
| 5. Incomplete outcome data | L | H | L | H | U | L | L |
| 6. Selective outcome reporting | L | U | L | L | U | L | H |
| Quality assessment | High | Low | Mod | High | Mod | High | High |