There’s no denying it’s hard to quit smoking, but new research suggests a way to make this difficult task a tiny bit easier. For the ladies, at least. According to a recent study, women who want to quit smoking may have better success by timing their quit dates with optimal days within their menstrual cycle. Although the technique may not promise any “miraculous” results, it’s worth a try.

A woman’s menstrual cycle can often have dramatic effects on her mood and personality, so why wouldn’t it affect her ability to give up nicotine, one of the most addictive substances on the planet? This was asked by drs. Reagan Wetherill and Teresa Franklin, two lead authors of an innovative new study on how changes in the female brain affect addiction. Working from the finding from previous research that quitting smoking is harder for men than for women, the team looked specifically at the effects of estrogen and progesterone, two natural sex hormones,  on addictive behavior in animals.

Although we’ve come to associate the word “menstrual period” with the week-long bleeding women experience once a month, in reality it describes a series of changes your body goes through in preparation for a pregnancy both before and after the monthly bleeds.

The follicular phase of the menstrual cycle begins the day a period starts. This phase usually lasts around two weeks and involves both the shedding of the uterine wall and it’s re-thickening again in preparation for a pregnancy. Here progesterone and estrogen levels are at their lowest. Once the follicular phase has ended, the luteal phase begins. This phase takes place during the 13 to 15 days from ovulation until menstrual bleeding, and is the time that women may experience premenstrual symptoms such as mood changes and weight gain. During the luteal phase, a woman's ovulation occurs, an egg gets released from the ovary, and hormone levels are high.

Past research has shown that during the follicular phase of the menstrual cycle, when the progesterone-to-estrogen ratio is low, women are more likely to be spurred towards addictive behavior, such as smoking for example. On the other hand, during the early pre-menstrual phase, also known as the luteal phase, when the progesterone-to-estrogen ratio is high, women are less likely to be tempted by addictive behaviors. Based on this, the team hypothesized that progesterone may help prevent a woman from relapsing to smoking during a cessation.

To test this theory, the team had 38 physically fit female smokers ranging from age 21 to 51 who were not taking hormonal birth control receive an MRI scan to examine regions of the brain responsible for controlling behavior and signalling rewards. The women were separated into two groups by whether they were in the follicular or luteal phase of their menstrual cycles and shown stimuli intended to tempt them to smoke, such as images of people enjoying cigarettes.

Results revealed that during the follicular phase when hormones were low, there was a reduced connectivity between regions of the brain that help make good decisions and those that contain the brain’s reward center. Wetherill and Franklin speculate that this could put women in this phase of their menstrual cycle at greater risk for continued smoking and relapse. Based on this information, the researchers believe that progesterone may protect against other addictions, including alcohol and foods high in fat and sugar.

Source: Franklin TR, Jagannathan K, Wetherill RR. Influence of menstrual cycle phase on resting-state functional connectivity in naturally cycling, cigarette-dependent women. Biology of Sex Differences . 2016