Summary of findings 2. Oral calcium compared with no treatment for treating leg cramps in pregnancy.

Oral calcium compared with no treatment for treating leg cramps in pregnancy
Patient or population: treating leg cramps in pregnancy Settings: outpatient clinic in Sweden Intervention: oral calcium Comparison: no treatment
Outcomes	Illustrative comparative risks* (95% CI)		Relative effect (95% CI)	No of participants (studies)	Certainty of the evidence (GRADE)	Comments
	Assumed risk with no treatment	Corresponding risk with oral calcium
Frequency of leg cramps after treatment: never	Study population		RR 8.59 (1.19 to 62.07)	43 (1 RCT)	⊕⊝⊝⊝ VERY LOW 1,2
	48 per 1000	409 per 1000 (57 to 1000)
Frequency of leg cramps after treatment	Study population		‐	60 (1 RCT)	⊕⊕⊝⊝ LOW
	The mean frequency of leg cramps in the control group was 0.95	The mean frequency of leg cramps in the intervention group was 0.53 lower (0.72 lower to 0.34 lower)
*The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: Confidence interval; RR: risk ratio
GRADE Working Group grades of evidence High certainty: further research is very unlikely to change our confidence in the estimate of effect. Moderate certainty: further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low certainty: further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low certainty: we are very uncertain about the estimate.

¹Serious design limitations (‐2).

²Few events and small sample size (‐1).

³Some concerns with design limitations (unclear selection bias) (‐1)

⁴Small sample size (‐1)