Table 2. Risk of bias assessment based on the Cochrane systematic review criteria for randomized interventions.

Study	Generation of random sequence	Allocation concealment	Blind method	Inadequate outcome assessment	Optional reporting	Other bias
Stokholm et al. (8)	Low	Low	Low	Low	Low	Low
Li et al. (9)	Low	Unclear	Low	Low	Low	Low
Goyal et al. (10)	Low	Low	Low	Low	Low	Low
Sié et al. (11)	Unclear	Low	Low	Low	Unclear	Low
Mandhane et al. (12)	Low	Low	Low	Low	Low	Low
Oldenburg et al. (13)	Low	Unclear	Low	Low	Unclear	Low
Mitjà et al. (14)	Low	Low	Low	Low	Low	Low
Saiman et al. (15)	Low	Low	Low	Low	Low	Low
Wang et al. (16)	Unclear	Low	Low	Low	Low	Low