<prompt> What is the minimum dose of ethinyl estradiol in OC pills for contraceptive effect?15mcg20mcg30mcg35mcg  <response>: For the average patient, the first choice of preparation for contraceptive purposes is a very low estrogen OC 20 mg EE unless there are other considerations, for example, previous pregnancy while taking the pill.Patients with persistent break-through spotting or bleeding could be offered a pill with the same low estrogen dose, but a more potent progestin, for example, levonorgestrel.Ref: Reference: Novaks gynaecology; 14th edition; Chapter 10; Family planning 