###Human: Is one tablet of Ovral I enough to prevent pregnancy? ###Assistant: Hi. The dose of Levonorgestrel is quite low in Ovral L compared to Unwanted 72. So the effectiveness for prevention of pregnancy, the two tablets of Ovral L may be sufficient. Now onward, please use regular protection and do not depend much on Unwanted 72. If the 72 hours have not passed, then you can take Unwanted 72 else or equal amount of Levonorgestrel, if it is already more than 72 hours then wait and watch for your scheduled time of the menses and if you miss your period then consult a gynecologist immediately.