Since the introduction of the combined hormonal contraceptive pill, dosages of ethinyl
estradiol (EE) have steadily decreased from more than 150mcg to 20mcg in an attempt to
improve the risk profile associated with the COC. In 2010, the Food and Drug Administration
approved a oral contraceptive pill containing EE 10mcg/NET acetate 1mg (Tradename Lo
loestrin). However, no studies have compared this formulation to pills containing either
higher doses of estrogen or progestin alone. It is not known whether EE 10mcg is sufficient
to prevent follicular development or to support the endometrium as well as higher doses of
EE. This trial addresses the question of whether an oral contraceptive pill with EE
10mcg/Norethindrone acetate 1mg will better suppress ovulation or have a better side effect
profile than a progestin only pill with a nearly equal dose of norethindrone.