How Second-Hand Smoke will affect your baby BEFORE you get Pregnant

By Julie Russell,

RN, Tobacco Prevention Specialist

Carter, Fallon, & Powder River County

Second-hand smoke could affect a woman’s baby before she has even conceived, a shocking new study reveals.

Decades of evidence have shown pregnant women who smoke or inhale second-hand smoke are more likely to deliver children with brain impairment that affects learning and behavior.

But new research by Duke University has shown this risk was identical in lab rats exposed to tobacco before conceiving.

The startling findings are an industry first, and will likely put pressure on health officials to ramp up the already-stringent public health policies on smoking.

And the researchers warn nicotine chemicals in e-cigarettes could be just as dangerous.

New research by Duke University has shown women exposed to tobacco before conceiving are more likely to deliver children with brain impairment that affects learning and behavior

‘Our study clearly shows there is no stage in which tobacco smoke is innocuous to the developing fetus,’ Dr Theodore Slotkin said.

‘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.’

Dr Slokin and his team are now scrambling to start investigations into how the destructive chemicals linger in the female body long enough to impair a fetus.

Smoke exposure during pregnancy damages regions of the fetal brain involved in learning, memory and emotional responses.  These were the exact symptoms found in the babies of rats exposed to smoke before conception.

To investigate, the team simulated secondhand smoke exposure by capturing and extracting the chemical compounds of tobacco smoke. This solution was administered to the rats through implanted pumps. They chose this method to eliminate the stress of breathing smoke, which in itself can potentially impact fetal brain development – a factor that made earlier studies less effective.

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 and tobacco smoke.

Damage was worst in rats exposed to smoke in late gestation. However, the impairments were stark in rats exposed before conception.

Specifically, the researchers found babies of rats exposed before conception had impaired function of the cholinergic brain circuits that govern learning and memory. The tobacco chemicals also affected the serotonin circuits that affect mood and emotional behavior.

‘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,’ Dr Slotkin, professor in Duke’s Department Pharmacology & Cancer Biology, said.

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.

Alternatively, the chemicals could be causing an epigenetic alteration in 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.

That finding suggests that e-cigarettes could also represent a significant hazard for women of childbearing age.

If you or someone you know needs help to quit tobacco please call the Quit Line at 1-800-QUIT NOW (1-800-784-8669) or go to  They have a special program for pregnant women.