Hi,
Usually antibiotics will not alter the menstrual cycles as per the literature available, the possible causes of your delayed periods are:
-Menstrual cycles with the length of 21 to 35 days can be considered as normal only, so this could be physiological delay.
-The infection leading to
stress and strain and altering the biological atmosphere of the body can lead to fluctuations in the reproductive hormone levels and that can lead to menstrual irregularity like delayed periods.
If you are still having any doubt regarding
pregnancy, please go for a
blood test for pregnancy, which can give more accurate result compared with a urine pregnancy test. If the blood test shows
serum beta HCG levels of less than 5 mIU/mL, the possibility of pregnancy can be ruled out. Then you can continue with your antibiotics and wait for a few more days you may get your periods soon.
Take care. Hope I have answered your question. Let me know if I can assist you further.
Regards,
Dr. Sree Gouri S. R., OBGYN