<prompt> Antiprogesterone compound RU-486 is effective for inducing abortion if the duration of pregnancy is:63 days72 days88 days120 days  <response>: RU486, i.e. Mifepristone, is an analogue of the progestin norethindrone, which has strong affinity for progesterone receptors but acts as an antagonist of progesterone.Given alone, the drug was moderately useful in causing abortion of early pregnancy, however the combination of mifepristone with analogue of prostaglandin E1 i.e. misoprostol is very effective. Combination of mifepristone and misoprostol is effective for inducing abortion within 63 days of amennorhea 