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נשים המעשנות במהלך ההריון עלולות לגרום לנזק קבוע לכלי הדם של התינוק - מעלות בכך את הסיכון שלו לשבץ ולהתקפי לב, כך דיווחו חוקרים בכינוס השנתי ה-47 של איגוד הלב האמריקני בנושא 'אפידמיולוגיה ומניעה של מחלות לב וכלי דם'.

המחקר - 'הסיכון לטרשת עורקים בהולנד בקרב צעירים' (ARYA) הראה כי משתתפים שנחשפו לעישון כשאמהותיהן היו בהריון סבלו מנזק קרדיווסקולרי (של הלב וכלי הדם) קבוע שניתן לזהות אותו בגיל הבגרות.

זהו הדוח הראשון המראה קשר זה, אמרו החוקרים, מהמרכז הרפואי של אוניברסיטת 'Utrecht' בהולנד. מדובר בגורם סיכון הניתן למניעה, הדגישו ואמרו כי נשים צריכות להפסיק לעשן, במיוחד במהלך ההריון, לא רק למען בריאותן שלהם אלא למען בריאות התינוק שטרם נולד.

Smoking during pregnancy can result in intrauterine growth retardation and low birth weight. Active and passive smoking in young adults also is associated with cardiovascular disease. But until the Dutch study, researchers were unsure whether this is due to a cumulative effect of smoke or whether children are vulnerable at specific periods, such as during gestation.

The study’s 732 participants were born in 1970-73 and vascular risk measurements were performed in 1999-2000. Uiterwaal and colleagues found that adult offspring of the 215 mothers who smoked during pregnancy had thicker walls of the carotid arteries in the neck. The carotid artery intima-media thickness (CIMT), an ultrasound measurement of the thickness of the inner walls of the neck arteries, is used to determine the level of atherosclerosis.

Offspring whose pregnant mothers were exposed to smoke had 13.4 micrometers thicker CIMT by young adulthood when compared to the offspring of mothers who did not smoke in pregnancy, researchers reported.

Even after the researchers adjusted for other risk factors in the young adults such as age, gender, body mass index, pulse pressure and cholesterol levels, the CIMT remained 9.4 micrometers thicker in children of mothers who smoked. Adjustment for current smoking by both mothers and fathers or the number of pack years (one “pack year” is 20 cigarettes smoked/day for one year) smoked by study participants also did not change this association.

“While it is difficult to separate the problem of current smoking and smoking during pregnancy, this study indicates that smoking in pregnancy has an independent effect,” Uiterwaal said.

If both parents smoked during pregnancy, the children as young adults had thicker CIMT than other participants with either one smoking parent or parents who didn’t smoke. Offspring of mothers who smoked the highest number of cigarettes during pregnancy had thicker CIMT than those born to mothers smoking less than the average or those who did not smoke.

“Our findings suggest that both smoking by mothers themselves in pregnancy and exposure to passive smoking are important,” he said. “More exposure leads to more vascular damage in the offspring.”

The researchers found that pregnancy was a critical period for damage from smoke exposure. They compared the children of mothers who didn’t smoke during pregnancy and were currently not smoking to the children of mothers who didn’t smoke in pregnancy but smoked now. They found no difference in CIMT. However, children from mothers who smoked in pregnancy, but who didn’t currently smoke had significantly thicker CIMT compared to offspring of abstaining mothers.

“There is the possibility that the compounds in tobacco smoke go through the placenta and directly damage the cardiovascular system of the fetus,” Uiterwaal said. “The damage appears to be permanent and stays with the children.”

When study participants were born, about 30 percent of the mothers smoked during pregnancy. But the current rate has dropped to between 5 percent and 7 percent due to health warnings, Uiterwaal said.

“There are still substantial numbers of mothers who smoke during pregnancy,” he said. “This is just another reason for expectant mothers not to smoke.”

This is the first study in which researchers have dealt with this issue. Uiterwaal said further evidence should come from additional studies that show similar results.

Michiel L. Bots, M.D., Ph.D., second author of the study and associate professor of clinical epidemiology at the University Medical Center Utrecht in The Netherlands, presented the findings at the American Heart Association meeting.

The study’s other co-author is Diederick E. Grobbee, M.D., Ph.D.

The ARYA study was funded by The Netherlands Organization of Health Research and Development Council.

Editor’s note: The American Heart Association strongly supports adequately funded, meaningful Food and Drug Administration (FDA) authority over the manufacture, sale, distribution, labeling and promotion of tobacco products. The association also advocates for smoke-free air policies, cigarette excise tax increases and comprehensive state tobacco control prevention and treatment programs.

Statements and conclusions of abstract authors presented at American Heart Association/American Stroke Association scientific meetings are solely those of the abstract authors and do not necessarily reflect association policy or position. The associations make no representation or warranty as to their accuracy or reliability.

NR07-1122 (EPI 07/Uiterwaal)

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