Most of the hormonal contraceptives contain a combination of estrogen and progesterone. They work by inhibiting the ovulation of the egg. They also make the cervical mucus relatively impermeable by the sperm. They don't prevent STDs. The most common side effect is breakthrough or unplanned bleeding. This is going to be especially true in the first 4 to 6 months. It can take that long for the pill to regulate the cycle. Any change in formulation before 3 months is likely premature. Also, as the dose of estrogen decreases, so does cycle control. Many of the newer pills have only 20 micrograms of ethinyl estradiol; correspondingly, breakthrough bleeding will be increased with these products. Patients taking other hepatically metabolized medicines such as anti-seizure medicine or chronic antibiotics like doxycyline should consider a higher formulation. I would also consider a higher formulation in patients weighing greater than 190 pounds. Most of the side effects from the pill will be due to the estrogen component. These include nausea, breast tenderness, fluid retention and decreased libido. Occasionally, the pill will cause an increase in blood pressure. There are certain patients to whom we would not give the pill. These include smokers greater than 35 years old (increased risk of deep venous thrombosis), patients with liver disease, patients with a personal or family history of thrombophilia (make clots easily, that is, factor 5 leidon mutation) and patients with breast or endometrial cancer. Some potential, but not certain contraindictions include women with migraines and high blood pressure. Some of the side benefits of the pill include cycle control, decreased volume of menses, decreased cramping or dysmenorrhea, reduced risk of ovarian and endometrial cancer by 40 percent, reduced risk of pelvic inflammatory disease and reduced acne.