Oral Contraceptives and Body Mass Index

This study is being conducted to understand how effective oral hormonal birth control (the pill) is for women with high body mass index ("BMI" - the ratio of your height and weight BMI"). Previous studies of birth control traditionally do not include women above a certain BMI number, so safety and efficacy is not clearly understood in this population, yet the pill is still widely used in women with high BMI. Reproductive-aged, ovulatory women of obese (BMI \>30 kg/m2), will be placed on oral contraceptives for 2 months, then randomized into two intervention arms for an additional 2 months. At several key time points, synthetic steroid pharmacokinetics, gonadotropins (LH, FSH) and ovarian hormone levels (estradiol, progesterone), ovarian follicular activity by ultrasound monitoring, and cervical mucus testing will be monitored.