Comparison 3. Supplementation with vitamin D + calcium + other vitamins and minerals versus calcium + other vitamins and minerals (but no vitamin D).

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Gestational diabetes (ALL)	1	1298	Risk Ratio (M‐H, Random, 95% CI)	0.42 [0.10, 1.73]
2 Maternal adverse events	1		Risk Ratio (M‐H, Random, 95% CI)	Subtotals only
2.1 Hypercalcaemia	1	1298	Risk Ratio (M‐H, Random, 95% CI)	0.0 [0.0, 0.0]
2.2 Hypercalciuria	1	1298	Risk Ratio (M‐H, Random, 95% CI)	0.25 [0.02, 3.97]
3 Preterm birth (less than 37 weeks' gestation) (ALL)	1	1298	Risk Ratio (M‐H, Random, 95% CI)	1.04 [0.68, 1.59]
4 Low birthweight (less than 2500 g) (ALL)	1	1298	Risk Ratio (M‐H, Random, 95% CI)	1.12 [0.82, 1.51]
5 Caesarean section	1	1298	Risk Ratio (M‐H, Random, 95% CI)	1.10 [0.95, 1.27]
6 Gestational hypertension	1	1298	Risk Ratio (M‐H, Random, 95% CI)	0.93 [0.31, 2.79]
7 Maternal death (death while pregnant or within 42 days of termination of pregnancy)	1	1300	Risk Ratio (M‐H, Random, 95% CI)	0.25 [0.02, 3.98]
8 Maternal vitamin D concentration at term (25‐hydroxyvitamin D) (nmol/L) (ALL)	1	635	Mean Difference (IV, Random, 95% CI)	75.17 [71.97, 78.37]
9 Birth length (cm)	1	1297	Mean Difference (IV, Fixed, 95% CI)	0.0 [‐0.28, 0.28]
10 Head circumference at birth (cm)	1	1297	Mean Difference (IV, Random, 95% CI)	0.0 [‐0.17, 0.17]
11 Birthweight (g)	1	1297	Mean Difference (IV, Random, 95% CI)	‐7.0 [‐55.95, 41.95]
12 Stillbirth	1	1300	Risk Ratio (M‐H, Random, 95% CI)	0.66 [0.29, 1.46]
13 Neonatal death	1	1298	Risk Ratio (M‐H, Random, 95% CI)	0.69 [0.22, 2.14]