Yosmin is a short-acting contraceptive and should be taken on time and in the correct dosage. If you have not had your period for 7 days after stopping taking a box of the drug, you should not take the next box of the drug, but wait and observe for 3 days, as long as you have your period within 3 days, you can take the next box of Yosmin. However, if you haven’t had your period for more than 10 days, this is the time to rule out the possibility of pregnancy. Although Yosmin is a short-acting contraceptive, it is not a 100% contraceptive and there is a 1%-2% chance of failure, so it is important to buy a pregnancy test if possible. If you rule out pregnancy, go to the hospital for an ultrasound to determine the thickness of the lining to decide when to take the next box of oral Yosmin. If possible, be patient and wait for a few more days, do not keep on taking Uthromycin, because the absence of withdrawal bleeding before taking the next medication of Uthromycin can cause a prolonged delay in menstruation.