Autonomic alterations in cocaine-exposed infants

Area of Science:

• Neonatal physiology
• Autonomic nervous system development
• Perinatal pharmacology

Background:

• Heart rate variability (HRV) indicates autonomic control.
• Intrauterine cocaine exposure is linked to decreased HRV in newborns.
• The persistence of HRV alterations in older infants is unknown.

Purpose of the Study:

• To prospectively evaluate HRV in infants exposed to cocaine in-utero.
• To determine if HRV alterations are transient or persistent.
• To investigate potential teratogenic effects of cocaine on the developing autonomic system.

Main Methods:

• Prospective evaluation of HRV in 2- to 6-month-old infants with in-utero cocaine exposure (n=71).
• Comparison with drug-exposed (non-cocaine, n=89) and normal control infants (n=77).
• Classification of cocaine exposure as light or heavy based on maternal usage percentile.

Main Results:

• Infants with in-utero cocaine exposure exhibited higher vagal tone and HRV (total power) compared to controls at 2-6 months.
• Increased vagal tone was primarily observed in the light cocaine exposure group.
• The heavy cocaine exposure group showed HRV and vagal tone similar to non-exposed infants.

Conclusions:

• Asymptomatic infants exposed to cocaine in-utero recover from initial low HRV by 2-6 months.
• Light cocaine exposure resulted in supra-normal vagal tone, indicating recovery.
• Blunted recovery in heavily exposed infants suggests a potential teratogenic impact of cocaine on autonomic development.