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.