Shahraki 2006.

Study characteristics
Methods	Open‐label, parallel‐group RCT
Participants	120 pregnant, multiparous women aged 25 to 35 years (mean age 29.2 years old) who suffered from muscular cramps and were in the 25th to 28th week of pregnancy when referred to a gynaecology clinic in Shahrekord, Iran
Interventions	Randomized to 3 groups: Group 1: 100 mg Vitamin E oral pill once a day (n = 40) Group 2: 8 cc of a 8% milk of magnesium suspension (267.2 mg elemental magnesium) 3 times a day, before meals (n = 40) Group 3: 500 mg calcium carbonate oral pill once a day (n = 40) All treatments administered for 45 days
Outcomes	Number of cramps over the last 24 hours Duration of cramps in seconds Cramp intensity (measured on a 1 to 10 points VAS) Frequency of low and high pain (1 to 5 = low pain rate and 6 to 10 = high pain) Each outcome measured on day 0, 45, and 90
Conflicts of interest	Funding and conflicts of interest not reported
Funding	Funding and conflicts of interest not reported
Notes	Published in English but likely translated from a different language, with the result that some information is incomprehensible. Conducted from September 2004 to July 2005
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	No information available on the method of randomization. Quote: “Each group was included 40 persons which were divided randomizly and turn of coming.” No table with baseline characteristics
Allocation concealment (selection bias)	High risk	No information available
Blinding of participants and personnel (performance bias) All outcomes	High risk	Open label
Blinding of outcome assessment (detection bias) All outcomes	High risk	Open label
Incomplete outcome data (attrition bias) All outcomes	High risk	120 initially included but results only presented for 90 participants. Paper only describes 20 participants quitting the study. Type of analysis unclear, likely to be per protocol
Selective reporting (reporting bias)	Low risk	All planned outcomes are addressed in the results
Cramp diary (recall bias)	Unclear risk	Unclear but given reporting was recall of the last 24 hours; unlikely that a diary was used
Other bias	Low risk	No obvious other bias