Accuracy and correlates of maternal recall of birthweight and gestational age

Background Links have been made between birth-weight (BW) and gestational age (GA) and health in child-and-adulthood. Because studies may rely on maternal recall, it is important to evaluate the quality of this information. Objective To determine the accuracy of maternal recall of children BW and GA, using the Danish Medical Birth Register (DBR) as reference and to examine the reliability of recalled BW and its potential correlates. Method The accuracy studies of BW and GA were composed respectively of 1271 and 678 mothers of schoolchildren, who participated the European Youth Heart Study. The reliability sample of BW was composed of 359 women. The agreement between the two sources was evaluated by mean differences (MD), intra-class correlations (ICC) and Bland-Altman’s plots. Misclassification of the various BW and GA categories were also estimated. Results There was high agreement between recalled and registered BW (MD = -0.2 g; ICC = 0.94) and GA (MD = 0.3 wk; ICC = 0.76). Only 1.6% of BW would have been misclassified into low, normal or high BW and 16.5% of GA would have been misclassified into pre-tem, term or post-term based on maternal recall. The logistic regression revealed that the most important variables in the discordance between recalled and registered BW were ethnicity and parity. Maternal recall of BW was highly reliable (MD = -5.5 g; ICC = 0.93), and reliability remained high across subgroups. Conclusion Maternal recall of BW and GA can provide accurate information for clinical and epidemiological use regarding fetal and infant growth.