|
| Study | Random sequence generation
(selection bias) | Allocation concealment
(selection bias) | Blinding of the participants and personnel (performance bias) | Blinding of outcome assessment
(detection bias) | Incomplete outcome data (attrition bias) | Selective reporting
(reporting bias) | Other bias |
|
| Alimohamadi et al. [11]. |
|
| Authors’ judgement | Low risk | Low risk | Low risk | Unclear | Low risk | Low risk | High risk |
| Support for judgement | Adequate method for randomization | Adequate allocation concealment | Blinding of the participants and personnel | No information for blinding of outcome assessors | No incomplete outcome data | Report of all outcomes | No intention to treat analysis |
|
| Czajkowski et al. [19]. |
|
| Authors’ judgement | Unclear | Unclear | Low risk | Unclear | Unclear | Low risk | High risk |
| Support for judgement | No information regarding the method used for randomization | No mention for the method of allocation concealment | Blinding of the participants and personnel | No information for blinding of outcome assessors | No information for the number of participants who were lost for follow-up according to subgroups | Report of all outcomes | No intention to treat analysis |
|
| El-Zibdeh and Yousef [12]. |
|
| Authors’ judgement | High risk | High risk | High risk | Low risk | Low risk | Low risk | High risk |
| Support for judgement | Quasi-randomized participants based on which day of the week the pregnant women came to the clinic | No allocation concealment | Neither blinding of the participants nor personnel | Adequate blinding for outcome assessors | No incomplete outcome data, analysis in all participants enrolled | Report of all outcomes | No intention to treat analysis for some variables |
|
| Gerhard et al. [13]. |
|
| Authors’ judgement | Unclear | Unclear | Low risk | Unclear | Unclear | Low risk | High risk |
| Support for judgement | No information regarding the method used for randomization | No mention for the method of allocation concealment | Blinding of the participants and personnel | No information for blinding of outcome assessors | No information for the number of participants who were lost for follow-up according to subgroups | Report of all outcomes | No intention to treat analysis |
|
| Hui et al. [20]. |
|
| Authors’ judgement | Unclear | Unclear | Unclear | Unclear | Unclear | Unclear | Unclear |
| Support for judgement | No information regarding the method used for randomization | No mention for the method of allocation concealment | No information | No information | No information | No information | No information |
|
| Omar et al. [14]. |
|
| Authors’ judgement | Unclear | Unclear | High risk | Unclear | Unclear | Low risk | High risk |
| Support for judgement | No information regarding the method used for randomization | No mention for the method of allocation concealment | Neither blinding of the participants nor personnel | No information for blinding of outcome assessors | No information for the number of participants who were lost for follow-up according to subgroups | Report of all outcomes | No intention to treat analysis |
|
| Pandian [15]. |
|
| Authors’ judgement | Low risk | Low risk | High risk | Unclear | Low risk | Low risk | Low risk |
| Support for judgement | Adequate method for randomization | Adequate allocation concealment | Neither blinding of the participants nor personnel | Unclear information for blinding of outcome assessors | No incomplete outcome data, analysis in all participants enrolled | Report of all outcomes | No additional bias |
|
| Palagiano et al. [16]. |
|
| Authors’ judgement | Unclear | Low risk | Low risk | Unclear | Unclear | Low risk | High risk |
| Support for judgement | No information regarding the method used for randomization | Adequate allocation concealment | Blinding of the participants and personnel | No information for blinding of outcome assessors | No information for the number of participants who were lost for follow-up | Report of all outcomes | No intention to treat analysis |
|
| Yassaee et al. [17]. |
|
| Authors’ judgement | Unclear | Unclear | High risk | Unclear | Low risk | Low risk | Low risk |
| Support for judgement | No information regarding the method used for randomization | No mention for the method of allocation concealment | No blinding of the participants | No information for blinding of outcome assessors | No incomplete outcome data, analysis in all participants enrolled | Report of all outcomes | No additional bias |
|
