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Smoking During Pregnancy Increases a Baby's Blood Pressure

MONDAY July 30 (HealthDay News/Dr. Tango)--A Dutch study shows that a baby born to a mother who smokes during pregnancy will have abnormally high blood pressure in the first few months of life.

One positive note in the report was that only 6% of the 456 women studied did smoke during pregnancy.

Smoking During Pregnancy Increases a Baby's Blood Pressure

However, babies born to those 30 women had systolic blood pressure that was 5.4 points higher on average than that of babies born to nonsmokers.

Systolic blood pressure is the higher of the two numbers used in a reading and it measures pressure when the heart is fully contracted. Researchers at the University of Utrecht Medical Center found no relationship between maternal smoking and diastolic blood pressure (the lesser number in the reading).

The real concern is that "blood pressure persists over time. Someone with high blood pressure at a young age usually becomes hypertensive later on in life," explained Daniel T. Lackland, professor of epidemiology at the Medical University of South Carolina and spokesman for the American Heart Association. Lackland didn't participate in the study.

Perhaps even more significant than the blood pressure results were the findings that babies born from mothers who smoked had significantly lower birth weights, were shorter and had a smaller chest circumference than babies of nonsmokers, Lackland said.

"One element that really stands out is this intrauterine growth retardation," said Lackland. "Smoking affects fetal life, therefore it essentially affects the baby for life."

The study, which is expected to be published in the September issue of Hypertension, did have some shortcomings, affirmed Dr. Michael Katz, vice president for research and global programs at the March of Dimes Birth Defects Foundation. For example, the study relied on questionnaires to obtain information about women's smoking habits, and these are not always reliable, he pointed out.

Regardless, the study does add support to the long-standing recommendation that no woman who is pregnant or who might become pregnant should smoke, Katz said.

"One thing you don't have to look for is another argument against smoking," he assured. "Every aspect of smoking is bad. It is one of the worst poisons that exists."

The increase in infant blood pressure could be significant if it persists, Katz warned. "What's very important is to know how long this lasts," he considered. "Is this a phenomenon that will wear itself out? A long term study would be required to find this out."

The Dutch researchers said they plan to follow the children for at least 4 to 5 years to see if the increase in systolic blood pressure persists.

Even if they find that the rise in blood pressure doesn't continue later on in life, Katz added that the study results "add an additional straw and the camel's back is breaking," referring to the many damaging effects maternal smoking has on the fetus. It never hurts to have one more piece of damaging evidence to present to women of childbearing age, he affirmed.

"Who knows at what point in the various arguments the conviction that smoking during pregnancy is bad will prevail?" he asked. "Women who have trouble with their blood pressure might be able to respond to this."

More information

For more detailed information on the dangers of smoking during pregnancy, visit the March of Dimes Birth Defects Foundation.

SOURCES: Daniel T. Lackland, M.D., professor, epidemiology, Medical University of South Carolina, Charleston; Michael Katz, M.D., senior vice president, research and global programs, March of Dimes Birth Defects Foundation, White Plains, N.Y.; September 2007, Hypertension© Author rights 2007, ScoutNews, LLC 

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