The ill effects of smoking cigarettes are felt in every organ of the body, including those that involve reproduction. Female smokers may experience difficulty getting pregnant and are more likely to have complications of pregnancy that affect their children; male smokers risk deterioration of sperm quality.
Women are more likely to become addicted to cigarettes than men and they have a more difficult time achieving success when they choose to stop smoking. A team of Canadian researchers thought there might be a connection between women’s nicotine addiction and fluctuating hormones during the menstrual cycle. They found the urge to smoke is strongest during specific phases of the cycle and suggest new interventions could be developed that harness the power of the menstrual cycle, making it easier for women to stop smoking.
At the Institut Universitaire in Santé Mentale de Montreal in Quebec, neuroscientist Dr. Andrianna Mendrek led a study of the brain activity in male and female smokers to see if fluctuating hormones influence nicotine cravings. The Mendrek study builds on the findings of previous studies that demonstrated:
- Women become nicotine-dependent sooner after they begin smoking than men do.
- Women have a harder time quitting smoking.
- Animal studies demonstrated that females will work harder than males to satisfy their nicotine cravings.
The Mendrek study involved 15 men and 19 women who each smoked more than 15 cigarettes a day. All study participants were right-handed and none of them was actively trying to kick the habit.
Each study participant underwent a functional magnetic resonance imaging (fMRI) scan as they viewed specially selected images; some of the images were deliberately neutral in subject matter but others were known to invigorate nicotine cravings. Each study participant smoked a cigarette about half an hour before undergoing the fMRI scan.
Men were scanned just once for the study. Women were scanned twice:
- Once during the follicular phase of their menstrual cycles (the first half, which begins at Day #1 of a period).
- Once during the middle of the luteal phase (which begins at ovulation and lasts until the next period starts).
Estrogen and progesterone levels were measured at the time of the fMRI.
The scans revealed similar brain activity for both women and men but the degree of activity in the women’s brains was significantly affected by the menstrual cycle:
- During the follicular phase (during menstruation), significant activity was mapped in the frontal, temporal, and parietal lobes.
- During the mid-luteal phase, only the right hippocampus was active.
According to Mendrek, “Hormonal decreases of estrogen and progesterone possibly deepen the withdrawal syndrome and increase activity of neural circuits associated with craving.” This finding suggests smoking interventions may be more effective for women if they are targeted to the luteal phase of the menstrual cycle (beginning at ovulation and lasting until the next period), when estrogen and progesterone levels are highest and cravings the least severe.
Although there are fewer smokers in the general population in recent years, the number of women smokers, especially young women, is increasing.
Sources:
- Mendrek, Andrianna, Laurence Dinh-Williams, Josiane Bourque, and Stéphane Potvin. "Sex Differences and Menstrual Cycle Phase-Dependent Modulation of Craving for Cigarette: An fMRI Pilot Study." Psychiatry Journal 2014 (2014). Web. 14 Jan. 2015.
- "Health Effects of Cigarette Smoking / Fact Sheet." CDC / Smoking & Tobacco Use. US Department of Health and Human Services, 21 Nov. 2014. Web. 14 Jan. 2015.