Table 2.

Summary of findings of 3 important longitudinal prospective studies

CATEGORY	OPPS9	MHPCD2,10	GENERATION R1,11
Gestational age and birth weight	Delivery at earlier gestational age in exposure group No differences in birth weight	Shorter gestation for exposure after first trimester only Increased birth weight after third trimester exposure	Fetal growth reduced from second trimester onward Lower birth weight in exposed group
Neonatal	Increased startle response	No differences in neonatal behaviour	Not examined
Infant	6 mo to 3 y: no neurobehavioural defects	Not examined	18 mo: increased aggression and inattention problems in exposed girls only
Preschool	4 y: poorer performance on verbal and memory subscales No effect on global intelligence	3 y: lower short-term memory and verbal reasoning scores	3 y: no significant deficits in cannabis-exposed group
School age	6 y: poorer sustained attention. No effect on impulse control Higher parental ratings of inattention and misconduct 6 to 9 y: impaired visual perception, visual memory, and language comprehension Increased distractibility	6 y: more impulsivity, hyperactivity, and delinquency 9 y: impaired abstract and visual reasoning Impaired executive functioning Poorer reading, spelling, and academic achievement Depressive and anxious symptoms	6 to 8 y: altered brain morphology in the frontal cortex
Teens and young adults	14 to 16 y: deficits in visual-cognitive functioning 17 to 22 y: deficits in executive functioning, response inhibition, and visual-spatial working memory Increased smoking and early substance use	14 to 16 y: deficits in academic achievement (especially reading), information processing speed, and visual motor coordination Increased rates of delinquency 17 to 22 y: increased rates of smoking and early initiation of substance use	Not yet examined

MHPCD—Maternal Health Practices and Child Development, OPPS—Ottawa Prenatal Prospective Study.