Researchers from the Perelman School of Medicine at the University of Pennsylvania suggests that the female smokers have a better chance of quitting if they timed their quit date with the optimal days within their menstrual cycle.

"Understanding how menstrual cycle phase affects neural processes, cognition and behavior is a critical step in developing more effective treatments and in selecting the best, most individualized treatment options to help each cigarette smoker quit," said Reagan Wetherill, PhD, a research assistant professor of Psychology and lead author of the study, in a statement.

Previously, researchers have shown that women in luteal phase of their menstrual cycle, or the period of time after ovulation and before menstruation, have enhanced responses to smoking cues, which are the people, places and things that they associate with smoking, compared to women in follicular phase of their menstrual cycle, the period after menstruation and continue until ovulation.

For the present study, researchers analyzed the resting-state functional connectivity (rsFC) of 38 physically healthy, premenopausal female smokers who were not taking hormonal contraceptives and are aging from 21 to 51 years, using a functional MRI scan.

The participants were divided into two groups. The first group consisted of 22 participants who were in the follicular phase of their menstrual cycle, while the remaining 16 participants were in the luteal phase of their menstrual cycle.

The results of their study, published in the journal Biology of Sex Differences, revealed that there was a reduced functional connectivity between the cortical control region, which helps in making good decisions, and ventral striatum, which contain the reward center, during the follicular phase. The weaker functional connectivity between cognitive control brain regions and reward signaling brain regions may result to lesser ability of the women to quit smoking. This suggests that women in the follicular phase and trying to quit smoking are more prone to continued smoking and relapse.

These findings support the previous study showing that progesterone may exert protective effects over addictive behavior. Furthermore, their study provides new insights into sex differences in smoking behavior and relapse.

"Interestingly, the findings may represent a fundamental effect of menstrual cycle phase on brain connectivity and may be generalizable to other behaviors, such as responses to other rewarding substances (i.e., alcohol and foods high in fat and sugar)," explained Teresa Franklin, PhD, a research associate professor of Neuroscience in Psychiatry and senior author of the study, in a press release.