Balance in Covariates Before and After Matching between the Low Maternal Expectations Group and the High Maternal Expectations Group.

Note. Each standardized mean difference is obtained by: mean in the low expectation group minus mean in the high expectation group, divided by the standard deviation in the low expectation group.1Mahalanobis distance used.2Exact matching used.3The average absolute standardized mean difference is the average of the absolute values of standardized mean differences for all covariates.Balance in Covariates Before and After Matching between the Low Maternal Expectations Group and the High Maternal Expectations Group.