Hello, Crisanta is a contraceptive pill,when used properly is over 99% effective. Common side effects such as nausea, dizziness, reduced menstrual flow, headache,breast tenderness are usually mild and short lasting. Any serious side effects like rashes,severe headache,fainting episodes,calf muscle pain, jaundice, breast lumps, to consult your gynecologist immediately. If not taken properly, can lead to contraception failure and pregnancy. It is contraindicated in women with pre-existing cardiovascular disease/liver disease, allergic to medication, in women who have a familial tendency to form blood clots, severe obesity and/or hypercholesterolemia (high cholesterol level), and used with precaution in smokers, in women who are on other medications. Contraceptive pills can be taken for a period of 2 years and conception after stopping the medications should not be a problem. Consider stopping the medication 3 months before planning conception and to start folic acid tablets 5 mg one daily. Period can be irregular for 2-3 months after stopping its use but regularizes itself.