Tobacco withdrawal symptoms and urges to smoke in pregnant versus non-pregnant smokers.

We compared tobacco withdrawal in pregnant and non-pregnant smokers abstaining from smoking for 24h. Female smokers completed an internet-based questionnaire, including the Minnesota Nicotine Withdrawal Scale-Revised (MNWS). They also rated additional withdrawal items and strength of urge to smoke. Consenting women were randomized to either: (i) abstain from smoking for 24h or (ii) smoke as usual. After 24h they rated their withdrawal again. We included a 'smoking as usual' group as we wished to establish that smoking abstinence increased withdrawal symptoms. Two-hundred and seventy-five women completed both the initial and the 24h questionnaire and reported abstaining (n=115, 17% pregnant) or smoking (n=160, 21% pregnant) as requested. Exclusively among abstinent smokers, we compared symptoms for the pregnant and non-pregnant groups. After 24h pregnant women had significantly lower scores than non-pregnant women for the mean MNWS (p=0.004) and for three individual MNWS symptoms (angry, p=0.010; anxious, p=0.048; impatient, p=0.011), with adjustments for baseline cigarette consumption and baseline withdrawal scores. Overall, on the first day of smoking abstinence, pregnant women are likely to report less severe tobacco withdrawal than non-pregnant women.