I have to take oral antibiotics before dental cleanings becuase of a heart murmur, on the bottle it says it makes BC ineffecitve. And to use another form of protection for the rest of the cycle. Also my Dentist always reminds me because he has more than one patient that got pregnant becuase of not using extra protection while on the oral antibiotics. So the answer to your question is YES it is very possible you are pregnant. Take a test to be sure.
Your doctor is going by old information. Here's one study:
Oral contraceptive efficacy and antibiotic interaction: a myth debunked.
Archer JS, Archer DF.
Department of Obstetrics and Gynecology, Medical University of South Carolina, Charleston 29425, USA.
The purpose of this study was to review the pharmacokinetic and clinical literature regarding the efficacy of oral contraceptives when used concomitantly with antibiotic therapy. Relevant literature was identified by searching MEDLINE and EMBASE. Other sources were located by consulting the bibliographies of the material collected from MEDLINE and EMBASE. Pharmacokinetic evidence demonstrates that plasma levels of oral contraceptive steroids are unchanged with the concomitant administration of antibiotics, including ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline. However, reduced steroid levels have been reported in women taking rifampin with oral contraceptives. Clinical reports of contraceptive failure with antibiotic use are retrospective, have multiple potential biases, and are not supported by pharmacokinetic data. Available scientific and pharmacokinetic data do not support the hypothesis that antibiotics (with the exception of rifampin) lower the contraceptive efficacy of oral contraceptives.
i am not so sure- my doc says when i am taking antibio. i need to use a condom-- even for some time after because anitbio stay in you for a few days after you stop taking them-- once your period is a week late make sure you take a test
You should be fine. Newer research shows that antibiotics (with the exception of rifampin) have no effect on the pill.