Table 2. Risk of Bias Assessment of Included Studies.

Article	Random sequence generation	Allocation concealment	Blinding of participants and personnel	Blinding of outcome assessment	Incomplete outcome data	Selective reporting	Other bias	Risk of bias
Manuela 2007(Brazil)	low	low	low	low	low	low	high	high
Monica 2010 (Norway)	low	low	low	low	low	low	high	high
Fabio 2010 (Brazil)	low	low	unclear	low	low	low	high	high
Ottar 2010 (Norway)	low	unclear	low	low	low	low	high	high
Padmini 2008 (India)	low	low	high	low	low	low	high	high