Mothers remember birthweights of adolescent children: the Muscatine Ponderosity Family Study.

The mothers of 127 adolescents living in Muscatine, Iowa were asked at the time of a clinic examination to recall their child's birthweight in pounds and ounces. For comparison, the hospital-recorded birthweight was obtained for each child. On the average, mothers underreported their child's birthweight by 1.3 oz. Sixty of 127 (47%) mother-reported birthweights were the same as those from hospital delivery records; 12% of the mothers overreported the birthweight by at least 5 oz and 17% underreported by at least that amount. The age of the mother and number of biological children were related to the ability to recall the birthweight exactly. The mean age of the children, and thus the average length of the mother's recall, was 16.1 years. Neither the length of recall, nor the mother's education, her current body size, or the current body size of the child were related to recall ability. However, mothers who overreported their child's birthweight were significantly shorter and lighter and their children tended to be taller and heavier, when compared to the mothers who underreported and their children. When the degree of agreement found in our study between reported and recorded birthweight exists, the effect of using reported rather than recorded birthweights in an epidemiological investigation is sufficiently small to allow inferences to be made regarding the relationship between birthweight and body size at mid-adolescence.