A 28-year-old female asked:

I am on birth control and was taking batrim can i get pregnant? when ihad a period on june 26th/ i am on my third week of my pills and i had intercourse on the 9th

2 doctor answers2 doctors weighed in
Dr. Geoffrey Rutledge
Internal Medicine 39 years experience
Some : Some antibiotics affect the effectiveness of birth control pills. Bactrim (sulfamethoxazole and trimethoprim) has been identified as one of the antibiotics that do interfere with the effectiveness of birth control pills. It is recommended that you use a back up method when having unprotected sex to prevent pregnancy while you are taking bactrim, (sulfamethoxazole and trimethoprim) and for atlease one week after you complete the regimen. If you had intercourse on june 9 and a period on june 26, then you were not pregnant at that time. Use a back up method anytime you take antibiotics and for one week afterward.
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Dr. Paula Hillard
Obstetrics & Gynecology 46 years experience
Most antibiotics OK : Some antibiotics, like rifampin, definitely interact with birth control.Others may in some individuals and with some pills .It probably depends on how your body metabolizes the drugs, and it may also depend on the dose of hormones in the pills.Most small studies don't show differences in the level of hormones in the blood, but to be on the absolutely safe side, use condoms during antibiotic use.
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Related questions

A 40-year-old female asked:
40 yr old, day 17 cycle, 8 month postpartum, Reg 28 day periods since march, spotted very light pink today, nothing else, no intercourse, no chance for pregnancy, no birth control, hashimotos, on phentermine, should I be concerned?
Dr. Audrey Lance
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Created for people with ongoing healthcare needs but benefits everyone.
A 18-year-old female asked:
I took bactrim (sulfamethoxazole and trimethoprim) once literally one pill while on birth control and had unprotected sex that day what are the chances of me getting pregnant?
Dr. Phillip Goebel
Emergency Medicine 18 years experience
Low probability: If you were taking your birth control like you were instructed it is a low probability of being pregnant. Please only take antibiotics as prescribed. ... Read More
Created for people with ongoing healthcare needs but benefits everyone.
A 19-year-old female asked:
I had intercourse a month ago . However i got my period a week after intercourse when i was supposed to since Im on birth control. And now I got it again . Can I still be pregant or no ?
Dr. James Ferguson
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Created for people with ongoing healthcare needs but benefits everyone.
A 30-year-old female asked:
Gave birth on Oct 25 2019, had intercourse on December 1. I believe I ovulated on November 30 or Dec 1 and I had a light 8 hrs period Dec 3. Is there a chance I could be pregnant?
Dr. Robert Kwok
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Maybe...: For fertile women who are having sex... it can be hard to tell if a woman is pregnant because some of the symptoms seen in early pregnancy can also ha... Read More
Created for people with ongoing healthcare needs but benefits everyone.
A 42-year-old member asked:
Does bactrim (sulfamethoxazole and trimethoprim) increase chances of getting pregnant if not on birth control?
Dr. Gerard Honore
Fertility Medicine 31 years experience
No. No.: Bactrim (sulfamethoxazole and trimethoprim) has no impact on getting pregnant eitehr way. None at all.
Created for people with ongoing healthcare needs but benefits everyone.
Last updated Oct 3, 2016

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