Among women who use oral contraceptives (OCs) correctly and consistently (not missing any pills and following instructions perfectly) only about 3 in 1000 (0.3%) are expected to become pregnant within the first year of use. The failure rates among “typical” users in the real world (read: not perfect) are estimated to be 8 in 100 becoming pregnant (8%). Clearly, there is a big difference between perfect use and typical use. There are many highly effective brands of OCs with varying combinations of drugs in them (progestin-only versus combined pills, and monophasic versus multiphasic pills). The side effects are largely dependent on the type of OC prescribed. It is best to consult a medical provider for specific drug and brand comparisons.