May 15, 2009 - Research

Genetic Variation May Make It Harder For Expectant Moms To Quit Smoking

For many women, finding out they’re pregnant is the kick in the pants they need to quit smoking.   But for some, a genetic variation may stand in their way.

The SNP is located in a cluster of genes on chromosome 15 that are involved in regulating the brain’s response to nicotine. Studies have already shown that the SNP is associated with nicotine addiction. Now a new report, published online last week in the journal Human Molecular Genetics, suggests that the effect of this variation is strong enough to overcome the maternal instinct and social pressure to protect one’s unborn child from the harmful effects of cigarette smoke.

British researchers studied 2,474 women who smoked regularly before becoming pregnant.   When questioned about smoking during their first trimester, 31% of the women with two Gs at had kicked the habit, compared to only 21% of the women with two As.   During the third trimester, 47% of women with two Gs were smoke-free, while only 34% of women with two As were.

Overall, after adjusting for pre-pregnancy smoking quantity, the researchers calculated that each A at increases a woman’s odds of continuing to smoke throughout her pregnancy by about 1.2 times.

The authors say their results show how genes can influence what is perceived by many to be a matter of self-control, but that “it’s in my genes” shouldn’t used as an excuse to avoid giving up smoking during pregnancy.

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