Article révisé par les pairs
Résumé : The relationship between low social class and low birth-weight or preterm deliveries is well established in singletons but not in twins. We present a study using all twin deliveries registered in Belgium in 1983 and in Aberdeen between 1951 and 1983. No significant relationship was found between social class and low birthweight, very low birthweight or preterm deliveries in the Belgian sample. In Aberdeen, we found significantly higher rates of low birthweight twins in low social classes. This increase of low birthweight twins in low social classes occurred in Aberdeen during the period 1951–1968, but not in the more recent data.