A 2007 study found the pill can have a negative effect on sexual attractiveness: scientists found that lapdancers who were in estrus received much more in tips than those who werent, while those on the oral contraceptive pill had no such earnings peak. Depression
Low levels of serotonin, a neurotransmitter in the brain, have been linked to depression. High levels of estrogen, as in first-generation COCPs, and progestin, as in some progestin-only contraceptives, have been shown to lower the brain serotonin levels by increasing the concentration of a brain enzyme that reduces serotonin. A growing body of research evidence has suggested that hormonal contraception may have an adverse effect on womens psychological health. In 2016, a large Danish study of one million women (followed-up from January 2000 to December 2013) showed that use of COCPs, especially among adolescents, was associated with a statistically significantly increased risk of subsequent depression, although the sizes of the effects are small (for example, 2.1% of the women who took any form of oral birth control were prescribed anti-depressants for the first time, compared to 1.7% of women in the control group). Similarly, in 2018, the findings from a large nationwide Swedish cohort study investigating the effect of hormonal contraception on mental health amongst women (n=815,662, aged 12–30) were published, highlighting an association between hormonal contraception and subsequent use of psychotropic drugs for women of reproductive age. This association was particularly large for young adolescents (aged 12–19).
The majority of women on cyclic COCPs have regularly scheduled withdrawal bleeding, which is vaginal bleeding mimicking users menstrual cycles with the exception of lighter menstrual bleeding compared to bleeding patterns prior to COCP commencement. As such, a recent study reported that out of 1003 women taking COCPs approximately 90% reported regularly scheduled withdrawal bleeds over a 90-day standard reference period. Withdrawal bleeding usually occurs during the placebo, hormone-free days. Therefore, avoiding placebo days can diminish withdrawal bleeding among other placebo effects. Effectiveness
If used exactly as instructed, the estimated risk of getting pregnant is 0.3% which means that about 3 in 1000 women on COCPs will become pregnant within one year. However, typical use of COCPs by users often consists of timing errors, forgotten pills, or unwanted side effects. With typical use, the estimated risk of getting pregnant is about 9% which means that about 9 in 100 women on COCPs will become pregnant in one year.