The purpose of this study is to investigate the pharmacokinetic interaction between the combination of ethinylestradiol and norethindrone and TMC278 25 mg once daily. Pharmacokinetics means how the drug is absorbed into the bloodstream, distributed in the body and eliminated from the body. Furthermore the short-term safety and tolerability (how well the body tolerates the drug) of co-administration of TMC278 and ethinylestradiol and norethindrone, in healthy women, will be assessed.