The aim of this study was to investigate the relations between pregnancy and childbirth factors and subsequent quality of maternal interactive behavior in a sample of 116 full-term infants and their mothers. Mothers reported on the conditions of childbirth when infants were 6-8 months of age, and their interactive behavior was observed during a home visit at 12 months. Results showed that mothers who did not report health problems during pregnancy and who had longer pregnancies, shorter hospital stays, natural deliveries, and infants with greater birthweight were found to be more sensitive during interactions with infants at 12 months. All these relations held after accounting for socio-economic factors and maternal psychological distress, except for the effect of type of delivery. This pattern of results, however, was almost exclusively due to mothers who already had at least one other child. Very few such relations were found among primiparous mothers. (Contains 3 tables.)