Table 2.
Risk of bias of the included studies
| Author, year, reference | Sequence generation | Allocation concealment | Blinding | Outcome data | Selective reporting | Other bias |
| Baruah, 201838 | Low | Low | Low | Low | Low | High |
| Basnet, 201230 | Unclear | Low | Low | Low | Low | Low |
| Bose, 200634 | Low | Low | Low | Low | Low | Low |
| Brooks, 200435 | Low | Low | Low | Low | Low | Low |
| Fataki, 201429 | Low | Low | Low | Low | Low | High |
| Howie, 201831 | Low | Low | Low | Low | Low | Low |
| Sempértegui, 201436 | Low | Low | Low | Unclear | Low | Low |
| Shah, 201237 | High | Low | Low | Low | Low | Unclear |
| Srinivasan, 201232 | Unclear | Low | Low | High | Low | Low |
| Valentiner-Branth, 201028 | Low | Low | Low | Low | Low | Low |
| Wadhwa, 201333 | Low | Low | Low | Low | Low | Low |