Comparison 1. Myo‐inositol versus control.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Gestational diabetes mellitus	3	502	Risk Ratio (M‐H, Fixed, 95% CI)	0.43 [0.29, 0.64]
2 Fasting OGTT	3	502	Mean Difference (IV, Fixed, 95% CI)	‐0.20 [‐0.28, ‐0.12]
3 One hour OGTT	3	502	Mean Difference (IV, Fixed, 95% CI)	‐0.68 [1.00, ‐0.37]
4 Two hour OGTT	3	502	Mean Difference (IV, Random, 95% CI)	‐0.75 [‐1.07, ‐0.43]
5 Hypertensive disorders of pregnancy	2	398	Risk Ratio (M‐H, Random, 95% CI)	0.43 [0.02, 8.41]
6 Caesarean section	2	398	Risk Ratio (M‐H, Fixed, 95% CI)	0.95 [0.76, 1.19]
7 Weight gain during pregnancy	2	411	Mean Difference (IV, Random, 95% CI)	0.64 [‐0.41, 1.70]
8 Relevant biomarker changes associated with the intervention	1		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
8.1 Total cholesterol	1	48	Mean Difference (IV, Fixed, 95% CI)	‐47.29 [‐52.87, ‐41.71]
8.2 Low density lipoprotein	1	48	Mean Difference (IV, Fixed, 95% CI)	‐33.50 [‐39.71, ‐27.29]
8.3 High density lipoprotein	1	48	Mean Difference (IV, Fixed, 95% CI)	‐13.79 [‐18.91, ‐8.67]
8.4 Triglycerides	1	48	Mean Difference (IV, Fixed, 95% CI)	‐39.33 [‐44.00, ‐34.66]
9 Adverse effects of intervention	2	245	Risk Ratio (M‐H, Fixed, 95% CI)	0.0 [0.0, 0.0]
10 Supplementary insulin	2	398	Risk Ratio (M‐H, Fixed, 95% CI)	0.48 [0.11, 2.09]
11 Gestational age at birth	2	398	Mean Difference (IV, Random, 95% CI)	5.50 [‐7.24, 18.24]
12 Preterm birth (less than 37 weeks' gestation)	2	398	Risk Ratio (M‐H, Fixed, 95% CI)	0.45 [0.17, 1.14]
13 Macrosomia	2	398	Risk Ratio (M‐H, Random, 95% CI)	0.35 [0.02, 6.37]
14 Birthweight	2	398	Mean Difference (IV, Random, 95% CI)	‐60.47 [‐265.21, 144.26]
15 Shoulder dystocia	2	398	Risk Ratio (M‐H, Random, 95% CI)	2.33 [0.12, 44.30]
16 Respiratory distress syndrome	1	197	Risk Ratio (M‐H, Fixed, 95% CI)	0.99 [0.06, 15.60]
17 Neonatal hypoglycaemia	2	398	Risk Ratio (M‐H, Fixed, 95% CI)	0.36 [0.01, 8.66]