A new study has suggested the oral contraceptive pill could shrink parts of the brain that govern a woman 's emotions . For the 100 million women worldwide on the contraceptive pill , the side effects are familiar . Mood swings , headaches and nausea , while more serious complications include blood clots and breast cancer . But scientists in California have added another potential cause for concern to the check list . Their new study has found the oral contraceptive shrinks two key regions of the brain , changing the way they function . The findings suggest the synthetic hormones found in the Pill cause these alterations in brain structure and function . Furthermore the ingredient is thought to suppress the natural hormones that occur when women take the Pill . Neuroscientists at UCLA examined the brains of 90 women , 44 of whom took the Pill , and 46 who experienced natural cycles . They found the lateral orbitofrontal cortex and the posterior cigulate cortex were thinner in those women taking the contraception . The lateral orbitofrontal cortex plays an important role in regulating a person 's emotions and their response to rewards . As a result the changes noted by researchers could , they say , be responsible for increased anxiety and depressive symptoms experienced by some women on the Pill . Meanwhile the posterior cingulate cortex governs the 'internal state ' , or inward-directed thought , helps process emotions and retrieve memories . Nicole Petersen , the study 's lead author , told The Huffington Post : 'Some women experience negative emotional side effects from taking oral contraceptive pills , although the scientific findings investigating that have been mixed . 'So it 's possible that this change in the lateral orbitofrontal cortex may be related to the emotional changes that some women experience when using birth control pills . ' Researchers said they do not yet know if these changes to the brain are permanent , or if they only last while a woman is taking the Pill . Dr Petersen said more research is needed , but added that this study is the first step . The latest study comes five years after research by the Royal College of General Practitioners revealed Pill-users have a 12 per cent reduction in their risk of developing cancer . Scientists at UCLA found the lateral orbitofrontal cortex and the posterior cigulate cortex were thinner in those women taking the contraception . They believe it could account for increased anxiety and depressive symptoms experienced by some women taking the Pill . The researchers studied 46,000 women across four decades , and found those on the Pill were less likely to die of cancer , heart disease or stroke . It contradicts past studies that have linked the Pill to breast cancer . The risks associated with taking the Pill are increased if a woman smokes , has a family history of thrombosis , is severely overweight , diabetic , has a high blood pressure or high cholesterol level . The study was published in the journal Human Brain Mapping .
Pill study found the UCLA shrinks two parts of the brain linked to emotion . Synthetic hormones found in the contraceptive are thought to be to blame . Believe it could account for increased anxiety and depressive episodes .