Very young infants, especially boys, who were exposed to tobacco smoke in the womb tend to have higher systolic blood pressure - the number on top of the reading - than their unexposed counterparts, results of a study in the Netherlands suggest.
Multiple investigations have revealed evidence of an association between mothers who smoke during pregnancy and higher blood pressure in their offspring, note Dr Cuno S.P.M. Uiterwaal and colleagues in the medical journal Hypertension. However, they add, the question remains as to whether the association occurs in the women or during the postnatal period.
To investigate, Uiterwaal's team at the University Medical Centre Utrecht measured blood pressure and heart rate among infants who were about 1 month old. Included were 363 infants whose mothers did not smoke, 63 whose mothers did not smoke but were exposed to smoke, and 30 whose mothers did smoke during pregnancy.
Blood pressure was measured three times in the lower leg of infants while they were sleeping. In comparing outcomes, the authors accounted for the possible influence of birth weight, gender, infant age at measurement, infant feeding, and maternal age.
Significant increase in BP
Maternal smoking was associated with a statistically significant 5.4 mm Hg increase in systolic blood pressure. Further analysis showed that the effect was not significant in mothers who were just exposed to smoking, and was limited to boys of mothers who smoked.
Girls' blood pressure was not affected significantly. No differences in diastolic blood pressure or heart rate were observed in boys or girls after adjustment.
Uiterwaal and associates intend to track these subjects during childhood to see if the relationship between tobacco smoke and blood pressure at birth is maintained later in life.
Source: Hypertension September 2007. – (Reuters Health)
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