Table 2.

Risk of bias summary: researcher’s opinions bout each risk of bias item for all included studies.

First Author (Year)	Randomization process	Deviations from intended interventions	Missing out come data	Measurement of the outcome	Selection of the reported result	Overall
Galland (2017)	+	+	+	+	+	+
Gradisar (2016)	+	+	+	+	+	+
Hiscock (2002)	+	+	+	+	+	+
Hiscock (2007)	+	+	+	+	+	+
Mindell (2011)	?	+	+	+	+	?
Mindell (2009)	?	+	+	+	+	?
Mindell (2018)	+	+	+	+	+	+
Paul (2016)	+	+	+	+	−	−
Rouzafzoon (2021)	+	?	+	+	+	?
Stremler (2013)	+	+	+	+	+	+

+  = Low risk, ? = Some concerns, − = High risk.