1. Table 1. Study design of the seven included trials.
| Study | Number/design/clinical Setting | Mean age (years) | % Female | Magnesium dose and route of administration | Frequency of administration | Treatment and assessment periods (days) | Washout period (days) | Comparator |
| Dahle 1995 | N = 73 Parallel Pregnancy |
Not given (child‐ bearing years) |
100% | 5 mmol combination Mg lactate + Mg citrate (122 mg elemental Mg) taken orally | Once each morning and twice each evening | Treatment 21 Assessment 21 |
Not applicable | Matched placebo tablet |
| Frusso 1999 | N = 45 Cross‐over Idiopathic |
61.6 | 73.3% | Mg citrate 900 mg tablet (100 mg elemental Mg) taken orally | Twice daily | Treatment 28 Assessment 28 |
28 | Matched placebo tablet |
| Garrison 2011 | N = 46 Parallel Idiopathic |
69.3 | 69.6% | 20 mmol Mg sulfate (486 mg elemental Mg) given intravenously | Once daily over 4 hrs on 5 consecutive days | Treatment 5 Assessment 90 |
Not applicable | Matched placebo solution |
| Nygaard 2008 | N = 45 Parallel Pregnancy |
30.9 | 100% | Mg lactate and Mg citrate chewable tablets containing 122 mg elemental Mg taken orally | Once each morning and twice each evening | Treatment 14 Assessment 14 |
Not applicable | Matched placebo tablet |
| Roffe 2002 | N = 73 Cross‐over Idiopathic |
62.9 | 54.3% | 1830 mg of tri‐magnesium dicitrate powder (300 mg elemental Mg) poured from a sachet into a glass of water taken orally | Once each evening | Treatment 42 Assessment during last 28 days of treatment |
First 14 days of second treatment period considered as washout |
Matched placebo powder |
| Rosenbaum 2011 | N = 40 Parallel Idiopathic |
66.6 | 57.5% | Slow release tablet of Mg lactate containing 84 mg of elemental Mg taken orally |
Two tablets twice daily | Treatment 30 Assessment 30 |
Not applicable | Matched placebo tablet |
| Sohrabvand 2006 | N = 84 Parallel Pregnancy |
Not given (child‐ bearing years) |
100% | 7.5 mmol magnesium aspartate (182 mg elemental Mg) taken orally. Unclear if tablet or powder / solution |
Twice daily | Treatment 14 Assessment 28 |
Not applicable | 3 different comparators 1) No treatment 2) 500 mg calcium carbonate tablet once daily 3)100 mg of thiamine (vit B1) plus 40 mg of pyridoxine (vit B6) once daily |
vit B1: vitamin B1