this is an excellent question because there is a lot of outdated information circulating about the effect of antibiotics on the effectiveness of birth control pills. let me start with your first question. i'm not aware of any studies that show amoxicillin affects the menstrual cycle in any way. however you will find a lot women claiming on internet forums that their period was delayed when they took amoxicillin. this doesn't mean it's true. many things (including illness) can affect your cycle. if you take amoxicillin and experience a delayed period in the future then you will have a good idea of whether or not this medication affects you in this way. to your second question: women for decades have been advised to use secondary (back-up) birth control if they take antibiotics while on birth control pills. this is prudent advice. however today it's thought only two specific antibiotics (rifampin and rifabutin) may actually decrease the effectiveness of birth control pills. so the amoxicillin should not affect your hormonal birth control but if you want extra peace-of-mind then use a condom until after you've finished the antibiotics. if you believe you may be pregnant you should take an at-home pregnancy test. if the test is negative then you should be ok to start your next pack of birth control pills on schedule whether or not your period arrived. if the pregnancy test is positive then obviously you should not take birth control pills but you should see a doctor to begin prenatal care wishing you well!
does amoxicillin alter your menstral cycle and does it interfere with my birth control pills. i went to urgent care and diagnosed was with an ear infection and really bad congestion. they prescribed amoxicillin to me but i didn't think to ask if it would interfere with my birth control. but my concern is that the day i started my antibiotic was the day my period was suppose to start. i typically don't start right on sunday more like monday night. but its now friday and i haven't started. i am suppose to start my new pill pack this coming sunday. should i be worried or is their an answer