Comparison 3. Sensitivity analysis (all trials) excluding trials with > 20% loss to follow up.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Preterm births	14		Risk Ratio (Random, 95% CI)	0.96 [0.90, 1.02]
2 Small‐for‐gestational age	10		Risk Ratio (Random, 95% CI)	0.92 [0.85, 0.99]
3 Low birthweight	14		Risk Ratio (Random, 95% CI)	0.88 [0.85, 0.91]
4 Perinatal mortality	12		Risk Ratio (Random, 95% CI)	1.02 [0.91, 1.15]
5 Stillbirths	13		Risk Ratio (Random, 95% CI)	0.97 [0.86, 1.08]
6 Neonatal mortality	11		Risk Ratio (Random, 95% CI)	1.03 [0.88, 1.20]
7 Maternal anaemia (third trimester Hb < 110 g/L)	8		Risk Ratio (Random, 95% CI)	1.03 [0.92, 1.15]
8 Miscarriage (loss before 28 weeks)	9		Risk Ratio (Random, 95% CI)	0.99 [0.94, 1.04]
9 Maternal mortality	5		Risk Ratio (Random, 95% CI)	1.13 [0.76, 1.68]
10 Very preterm birth (before 34 weeks of gestation)	4		Risk Ratio (Random, 95% CI)	0.81 [0.71, 0.93]
11 Congenital anomalies	2		Risk Ratio (Random, 95% CI)	1.34 [0.25, 7.12]
12 Neurodevelopmental outcome: BSID scores	1		Mean Difference (IV, Random, 95% CI)	Subtotals only
12.1 Mental development scores at 6 months of age: new subgroup	1	592	Mean Difference (IV, Random, 95% CI)	‐0.02 [‐6.75, 6.71]
12.2 Mental development scores at 12 months of age	1	572	Mean Difference (IV, Random, 95% CI)	1.21 [‐5.04, 7.46]
12.3 Psychomotor development scores ar 6 months of age	1	592	Mean Difference (IV, Random, 95% CI)	‐0.16 [‐3.89, 3.57]
12.4 Psychomotor development scores at 12 months of age	1	572	Mean Difference (IV, Random, 95% CI)	0.34 [‐2.72, 3.40]
13 Mode of delivery: caesarean section	4		Risk Ratio (Random, 95% CI)	1.13 [0.99, 1.30]