By its many advantages, pills are one of the most used methods in the world and in Senegal. On the other hand, exist side effects which can limit their utilization. Our study concern 35 women using between 12 and 36 months mini pills, which might produce low side effects. In our users, biochemical parameters are modified but not pathologic. By our results, we think that in the following 5 or 10 years, these alterations might increase; so, we raise the alarm and propose a biological following up of the oral contraceptive users.