Reliability of Parental Recall of Birth Weight, Birth Length and Gestational Age in the Multicenter Cohort Study IDEFICS

Objective: To investigate the reliability of parental recall of birth weight, birth length and gestational age several years after birth. Methods: Parentally recalled birth parameters were obtained from the European multicentric cohort study IDEFICS (Identification and prevention of dietary- and lifestyle-induced health effects in children and infants) and compared to the corresponding data externally recorded in the child’s medical check-up booklet. The agreement between the two sources was examined using Bland–Altman plots, intraclass correlation coefficients and Cohen’s kappa for clinically relevant categories. Additionally, logistic regression models were used to identify factors related to parental recall accuracy. Results: A total of 4930 children aged 2 to 11 years were included. Accuracy of birth weight within 100 g was 88%, 94% of the recalled birth length was within 2 cm, and 99% of the parents could recall with 2 weeks accuracy how many weeks their child was delivered preterm. Discrepancies of more than two weeks or more than 100 g were more likely in parents of low or medium socioeconomic status. Non-biological parents were 3.4 times more likely to have a discrepancy of more than 100 g compared to biological mothers (95% CI 1.7–6.7). Moreover, parents were less likely to accurately recall their child’s birth parameters with increasing number of children within a family. Conclusions for Practice.: In general, parents’ information matched well with the medical check-up booklet. However, accuracy varied among different groups which should be taken into consideration when using birth data recalled by parents in studies of child health.