Table 2: Meta-analyses of RCTs of dietary and nutrient interventions in the management or prevention of gestational hypertension
Interventions	Outcome	Total sample size	No. of RCTs	OR (and 95% CI)
Dietary advice v. no advice33	Preeclampsia	136	1	0.86  (0.33-2.22)
Isoenergetic balanced protein supplementation v. no supplementation34	Pre-eclampsia	782	1	1.00  (0.55-1.88)
Balanced protein and energy supplementation v. no supplementation35	Pre-eclampsia	516	3	1.25  (0.72-2.17)
Restriction of energy intake v. no restriction in overweight women36	Pre-eclampsia	284	2	1.15  (0.55-2.40)
Low v. high salt intake37	Hypertension	36	1	1.78  (0.28-11.52)
	Proteinuria	36	1	1.12  (0.07-18.75)
Prophylactic magnesium supplementation v. placebo38,39	Pre-eclampsia	942	2	0.94  (0.61-1.44)
Magnesium supplementation in women with established hypertension40	Use of antihypertensive drugs	58	1	1.54  (0.55-4.28)
Prophylactic calcium supplementation v. placebo41	Hypertension	1729	6	0.44  (0.33-0.59)*
	Proteinuric pre-eclampsia	1729	6	0.34  (0.22-0.54)*
Calcium supplementation v. placebo in women with established pre­eclampsia42	Severe pre-eclampsia	75	1	1.05  (0.43-2.59)
Zinc supplementation v. no supplementation43	Hypertension	656	2	0.76  (0.37-1.60)
Iron supplementation v. no supplementation44	Proteinuric hypertension	203	3	0.74  (0.25-2.20)
Folate supplementation v. no supplementation45	Proteinuric hypertension	936	3	1.28  (0.86-1.90)
*Statistically significant.

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