Infant autonomic function is altered by maternal smoking during pregnancy

Area of Science:

• Neonatal physiology
• Autonomic nervous system function
• Cardiovascular regulation

Background:

• Sudden infant death syndrome (SIDS) is linked to smoking during pregnancy.
• Autonomic control mechanisms may be subtly altered in infants of smokers.
• Head-up tilt tests and heart rate variability analysis assess autonomic function.

Purpose of the Study:

• To investigate the impact of maternal smoking on infant cardiovascular responses to head-up tilt.
• To compare autonomic responses between infants of smokers and non-smokers at different ages.

Main Methods:

• Passive 70-degree head-up tilt test performed on infants.
• Blood pressure and heart rate variability were monitored.
• Comparison between infants of smokers and non-smokers at 2-3 days and 3 months of age.

Main Results:

• No significant differences in heart rate variability indices were found between groups.
• At 2-3 days, infants of smokers showed a significant decrease in systolic blood pressure during tilt (P<0.01).
• At 3 months, systolic blood pressure remained unchanged in infants of smokers but increased in controls (P<0.05).

Conclusions:

• Maternal smoking significantly alters infant blood pressure regulation during head-up tilt.
• These findings suggest impaired autonomic cardiovascular control in infants exposed to maternal smoking.
• The observed alterations may contribute to the increased risk of SIDS in infants of smokers.