Maternal Smoking during Pregnancy and Regional Brain Volumes in Preterm Infants

Objective

To evaluate the association between maternal smoking during pregnancy and both brain volumes and head circumference in very-low-birth-weight/very-low-gestational-age infants.

Study design

The PIPARI Study is a prospective follow-up study of infants with a birth weight ≤1500 g or a gestational age <32 weeks born in 2001 to 2006 (n = 232) at Turku University Hospital. The brain was imaged by serial brain ultrasound examinations until discharge and magnetic resonance imaging at term age. The head circumference was measured at birth, term, and 2 years corrected age. These measures were correlated to maternal smoking during pregnancy as reported by the mothers.

Results

The prevalence of maternal smoking was 18%. The frontal lobe (P = .01) and the cerebellar (P = .03) volumes were significantly smaller in the exposed than in the unexposed infants. The volumes of the other parts of the brain did not differ. There was no association between prenatal smoking exposure and head growth or structural brain disease.

Conclusions

Prenatal smoking exposure was associated with significantly smaller frontal lobe and cerebellar volumes in the brains of preterm infants. This is consistent with reports showing an association between prenatal smoking exposure and impairments in frontal lobe and cerebellar functions such as emotion, impulse control, and attention.

ADHD, Attention deficit and hyperactivity disorder, ICC, Intraclass correlation coefficients, IVH, Intraventricular hemorrhage, MRI, Magnetic resonance imaging, VLBW, Very-low-birth-weight, VLGA, Very-low-gestational-age