Skip to content


    Exciting News for WebMD Members!

    We've been busy behind the scenes building new message boards for you. You'll have new and easier ways to find messages, connect with others, and share your stories.

    And, this will all be available on your smartphone or other mobile device!

    What Do You Need to Do?

    The message board you're used to will be closing in the coming weeks. While many of your boards will be making the move to our new home, your posts will not. Want to keep a discussion going? Save posts you want to continue (this includes your member profile story), so that you can re-post them in the new message boards.

    Keep an eye here and on your email inbox, we'll be back in touch soon to give you all the information you need!

    Yours in health,
    WebMD Message Boards Management

    Bactrim and pregnancy test???
    num1mom2006 posted:
    My LMP was 6/8/09. I started a 10 day regiment of SULFAMETH/TRIMETHOPRIM 800/160 TABS (generic for Bactrim DS) on the 26th of June. I missed one does causing me to take my last dose on 7/06/09. The day my period was due. We have been TTC for 6 months now. And my period is now a week late but I took a test on the 6th, 7th, 8th, 9th, and 10th. All came up negative. I haven't taken a test since. It is now the 12th and my period still hasn't come. This will be my fourth pregnancy and child. I have several other symptoms which include... breast tenderness. back pains, difference in acne (cleared up just like with other) and besides the missed period I am also noticing breast discharge. The only other time I have ever had this happen was when I was pregnant. So I guess my question is can the Bactrim cause a false negative result? Since Bactrim makes you pee a lot and is secreted in urine is it possible that it altered the amount of HcG in my urine? I know that false negative are fairly common. But what are the chances of taking a test 18 days past ovulation and having a false negative result? I have read everything that I can find on Bactrim but I can't seem to find anything about how long it stays in the system after the last dose or how it effects the urine. Thanks, Connie

    Helpful Tips

    Be the first to post a Tip!

    Expert Blog

    Below the Belt: Women's Health - Jane Harrison-Hohner, RN, RNP

    From HPV to irregular periods to PMS to fibroids, Jane Harrison-Hohner, RN, is here to share her knowledge and insight...Read More

    Report Problems With Your Medications to the FDA

    FDAYou are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.