Hello dear Understand your concern. Yes you can take emergency contraception like unwanted 72 . You should take up to 72 hours after having unprotected sex. Unwanted 72, is a single tablet containing 1.5 mg of synthetic progestin, Levonorgestrel. For this emergency contraception to be effective, it is necessary to take one 1.5 mg pill of Levonorgestrel on a single day and within 72 hours of unprotected intercourse. Best results are seen when Unwanted 72 is taken quickly, within 72 hours of an event, as it takes 72 hours after fertilization for a woman’s body to produce a pregnancy. The level of protection provided by Unwanted 72 is as follows: If taken within 24 hours – up to 95% effective If a woman should vomit after taking Unwanted 72, it is recommended to repeat the one time dose for effectiveness in pregnancy prevention. It cause period may be delayed/early as a side effects due to hormonal imbalance. So better to avoid tablet post pone the period. If period will not come. You should consult the gynecologist and undergo following tests: Pelvic examination USG CBC Hormonal analysis. Hope this may help you Best regards Dr. sagar