New Animal Study Shows Harmful Effects Of Secondhand Smoke Even BEFORE Pregnancy

A new animal study has highlighted the harmful effects of secondhand smoke even before pregnancy. Researchers at Duke University in the US have found that exposure to cigarette smoke - even before conception - appears to have a lingering impact that can later impair the brain development of a foetus. The researchers used rats in experiments that were carefully designed to mimic the second-hand smoke exposure that humans encounter. They found that the chemical components of tobacco smoke affect foetal brain development throughout pregnancy. The results of the study show that smoke exposure damages the parts of the brain involved in learning, memory and emotional responses. Although the impact was most severe with exposures occurring in late pregnancy, adverse effects on the foetuses' neuro-development occurred even when the mothers were only exposed prior to conception. Professor Theodore Slotkin, of Duke's department of pharmacology and cancer biology, commented on the new findings:

"This finding has important implications for public health, because it reinforces the need to avoid secondhand smoke exposure not only during pregnancy, but also in the period prior to conception, or generally for women of childbearing age.

Our study clearly shows there is no stage in which tobacco smoke is innocuous to the developing fetus. We warn women about smoking during pregnancy, and most people are aware that secondhand smoke exposure is also harmful to the fetus, but our study is the first to show that exposure prior to conception is potentially damaging, as well. The public health implications should be obvious."

Slotkin and his colleagues simulated secondhand smoke exposure by capturing and extracting the chemical compounds of tobacco smoke and administering the solution through implanted pumps in the lab rats. That process eliminated the stress of breathing smoke, which in itself can potentially impact fetal brain development - a factor that had confounded earlier studies on the effects of tobacco smoke. Groups of female rats received the tobacco smoke extract during one of three periods: prior to mating, early gestation or late gestation. The researchers then studied the offspring starting in early adolescence and into adulthood, focusing on brain regions that are known to be adversely affected by nicotine. The researchers found that exposure to tobacco smoke extract in all three of the study periods resulted in the offspring having impaired function of the brain circuits that govern learning and memory, and of the circuits that affect mood and emotional behaviour. The researchers said more study is needed, but potential causes include the lingering effects of some of the smoke components, which can remain in the body for several days after exposure. They also suggested that the chemicals might change the mother rat's metabolism or hormonal status, or they could be causing a change to the egg, which affects the activity of genes that control brain function. A prior study from the same team found a substantial portion of the tobacco smoke effect resulted from the nicotine in the smoke; a finding that suggests e-cigarettes could also represent a significant danger.  Join the conversation on Twitter @HerFamilydotie