Introduction: Most pregnant smokers report abruptly reducing their cigarettes per day (CPD) by ~50% shortly after learning of pregnancy and of making further smaller reductions over the remainder of their pregnancy. Laboratory and naturalistic studies with non-pregnant smokers have found that these types of reductions often lead to changes in smoking topography (i.e., changes in smoking intensity to maintain a desired blood-nicotine level). 19, 20 If pregnant women engage in compensatory smoking, they may expose themselves and their offspring to the same level of toxicants despite reporting reductions in CPD. Methods: Pregnant and non-pregnant female smokers (n = 17 and 91, respectively) participated. At the experimental session, after biochemical confirmation of acute abstinence, all participants smoked one of their usual brand cigarettes ad lib through a Borgwaldt CReSS Desktop Smoking Topography device. Carbon monoxide (CO) and measures of nicotine withdrawal, craving, and reinforcement derived from smoking were also collected. Results: The two groups did not differ on any demographic or smoking characteristics at screening, except nicotine metabolism rate, which as expected, was faster in pregnant smokers. Analyses suggest that none of the smoking topography parameters differed between pregnant and non-pregnant smokers, although pregnant smokers had a significantly smaller CO boost. Both groups reported similar levels of relief of withdrawal and craving after smoking, but other self-report data suggest that pregnant smoker find smoking less reinforcing than non-pregnant smokers. Conclusions: Pregnant smokers do not smoke cigarettes differently as compared to non-pregnant female smokers, but appear to find smoking less reinforcing.