The maternal factors during pregnancy for intrauterine growth retardation: An umbrella review.

The criteria for level of evidence classification criteria convincing evidence (Class I): More than 1,000 cases, significant summary associations ( p < 10 −6 ) per random-effects calculations, no evidence of small-study effects (Egger < 0.1), no evidence of excess of significance bias, prediction intervals not including the null value, largest study nominally significant ( p < 0.05), not large heterogeneity ( I 2 < 50%), and robust results based on sensitivity analysis.

also in 7,732 other papers