Thanks for the query at ATD.
Plan -b is an emergency contraceptive pill can be taken within 72 hrs immediately after unprotected sex.
Plan-b is 95% effective if taken within 24 hours, so failure rate is also there.
As it contains high doses of hormone in it, it may cause pregnancy like symptoms like nausea, vomiting, headache etc. The symptoms may mimic pregnancy. If your home pregnancy test showing negative, then you may ignore and wait for the withdrawal bleeding. If the menstrual is delayed, you may take a blood hCG test.
Hope found useful, feel free to ask more information.
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