They include breakthrough bleeding, nausea, mood changes, acne, weight changes, mood changes, breast tenderness, decreased libido, and headaches. Breakthrough bleeding may be due to inconsistent use, and it is more frequent in smokers. There is little scientifically rigorous comparative data between the different pill formulations available, but in 725 studies using various formulations spotting, breakthrough bleeding, and amenorrhea occurred in only about 10 percent of users after six months. After breakthrough bleeding, breast tenderness and nausea are leading reasons why women stop taking the pill. These conditions are likely due to estrogen, so switching to a formulation containing less estrogen may solve any persistent problem.
Nausea is very infrequent with current low-dose pills.
Patients who experience side effects should be counseled to keep taking the pill as most of them improve with time. If side effects persist or become intolerable, changing to a different pill is an option, as is changing to a different contraceptive method. These alternatives should be fully discussed with a health care provider before a patient stops taking the pill.