Swedish researchers reported in Hypertension, Journal of the American Heart Association that newborns of women who smoked during pregnancy show signs of circulatory dysfunction in the first few weeks of life that get worse throughout the first year. The blood pressure response to tilting the infants upright during sleep, a test of how the body copes with repositioning, was dramatically different in infants born to smoking mothers compared to those born to nonsmoking parents, the study found.
Infants not exposed to tobacco experienced only a 2 percent increase in blood pressure when they were tilted upright at one week of age and later a 10 percent increase in blood pressure at one year. Infants of smoking mothers had the reverse, a 10 percent increase in blood pressure during a tilt at one week and only a 4 percent increase at one year. At three months and one year, the heart rate response to tilting in the tobacco-exposed infants was abnormal and highly exaggerated, researchers reported.
“Babies of smokers have evidence of persistent problems in blood pressure regulation that start at birth and get worse over time,” said Gary Cohen, Ph.D., lead author of the study and senior research scientist in the Department of Women and Child Health at the Karolinska Institute in Stockholm, Sweden. “This study reveals for the first time that early life exposure to tobacco can lead to long-lasting reprogramming of infant blood pressure control mechanisms.”