Maternal drug use during pregnancy: are preterm and full-term infants affected differently?

This study examined whether preterm infants are more vulnerable to the effects of prenatal drug exposure than are full-term infants. The sample of 235 low-income African American mothers and their infants included 119 cocaine-polydrug users, 19 alcohol-only users, and 97 nonusers; 148 infants were full term and 87 were preterm. Direct effects of exposure on birth weight, birth length, ponderal index, and irritability were moderated by length of gestation: Fetal growth deficits were more extreme in later-born infants, whereas increases in irritability were more extreme in earlier born infants. Effects of exposure on cardiorespiratory reactivity to a neonatal exam were not moderated by length of gestation. In general, effects of exposure occurred for both cocaine-polydrug and alcohol only users and so could not be unambiguously attributed to either of these drugs alone.