Table 1.

Meta-analyses of confounding variables.

Meta-analysis	k	Effect size	95% CI	p	Heterogeneity
					I2	p
Gestational age (MD)	18	0.63 weeks	0.24 to 1.03	0.002	94%	<0.001
Birth weight (MD)	18	−379 g	−452 to −306	<0.001	97%	<0.001
Antenatal corticosteroids (OR)	17	1.18	0.94 to 1.49	0.159	59%	0.001
Respiratory distress syndrome (OR)	23	0.77	0.60 to 0.98	0.035	78%	<0.001

CI: confidence interval; k: number of studies; MD: mean difference (growth restricted group minus control group); OR: odds ratio.