The impact of birth order on mother-infant interactions in preterm and sick infants.

Maternal-infant interaction patterns were observed for high-and low-risk, first-, and later-born infants at 3 months of age. The high-risk subjects included healthy preterm infants, sick preterm infants, and sick full-term infants. "Sickness" at birth was defined as respiratory distress or birth asphyxia. The low-risk group consisted of healthy full-term infants. The subjects were divided into first-born and later-born groups. Birth order was expected to interact with prematurity and illness in affecting maternal behavior. Multivariate analyses of variance indicated that this was the case; birth order had a significant impact among the high-risk but not the low-risk subjects. First-born preterm infants received more overall maternal stimulation than later-born preterms. Sick first-borns had more responsive mothers than sick later-born infants. The results suggest that high-risk later-born infants may be at greater risk as a result of both birth trauma and less optimal maternal interaction patterns.