RESUMEN
OBJECTIVE: To investigate the association between poverty, birthweight, and infant weight gain in Hertfordshire, 1923-1939. DESIGN: Cohort study based on the Hertfordshire Health Visitors' Register (HHVR). SETTING: The population of Hertfordshire, and a sub-sample of five Hertfordshire towns-Hoddesdon, Berkhampstead, Hertford, Hitchin, and Bishops Stortford-extracted from the HHVR. SUBJECTS: Some 71 201 live birth entries in the HHVR and a sample of 13,649 live birth entries for the five towns. MEASURE OF POVERTY: Rateable value of birth addresses reflecting market and rental value of housing. MAIN OUTCOME MEASURES: Birthweight, and infant weight gain (z score of weight at one year minus z score of birthweight). RESULTS: In Hertfordshire as a whole there was a reduction in mean birthweight from 7.7 pounds (lbs) in 1923 to 7.4 lbs in 1939. Over the same time period there was an increase in mean infant weight gain, although with a degree of variation within the trend. In the sample of five towns there was no association between rateable value and birthweight, but a significant association between rateable value and both weight at one year, and weight gain during the first year of life. CONCLUSION: In Hertfordshire average birthweight declined, whereas weight gain during the first year of life tended to increase, at a time when, nationally, calorific intake and per capita consumption of a range of nutritional ingredients was rising. Poverty, as measured by rateable value, did not correlate with birthweight but was associated with weight gain during the first year of life. These findings suggest that nutritional poverty had a more significant influence on post-natal weight gain than it did on birthweight.