Nitrates in sample-what are they and why do I need penicillin for them?

[Elsqueak]

Have just been given meds to treat "nitrates" found in my urine sample. Am 27wks and have zero uti symptoms so was surprised I needed presciption. Generally hate having to take antibiotics as (sorry tmi) gives me cramps and diahorrea. However will suffer this for benefit of baby. What are these "nitrates" and why didn't they give me any symptoms? Am worried I could have had these for ages and not noticed.
How could they affect Baby?

Sure someone else will be able to give a better answer soon, but I think nitrates are the products of bacterial decomposition/waste products & can therefore indicate an infection. I would imagine there is minimal risk to baby etc but the antibiotics are being prescribed to wipe out any bacteria before they get going properly.

It's nitrites and chunkychicken is correct in what they are. No-one likes to take medicines unnecessarily but the guidelines for treating UTI in pregnant and non-pregnant women are different. They are super-cautious about treating pregnant women based on urine tests even if asymptomatic. Untreated UTI in pregnancy can lead to pre-term labour and IUGR, as well as long-term kidney complications for the mum.
They'll send you're sample off to the lab and if it confirms there definitely is an infection there then you'll have alreay begun treatment which is great. If it comes back saying you don't have an infection they might suggest stopping the abx.
There are a few abx that are recommended for initial empirical (best-guess) treatment of uti and some are more or less likely to cause diarrhoea than others; your dr might be able to prescribe one thats less likely to do so.
I wouldn't worry too much about how long they've been there for. I assume you give in urine samples at your antenatal appointment and if so they are tested for at every visit

Thanks both for reading and responding. Had no idea could lead to pre-term labour! Thanks for explaining nitrates...yuk. Am so far not doing too bad on these abx, only slight cramping so will persevere as directed. Is it worth drinking cranberry juice as a preventative measure?

It is advised that you drink a glass of cranberry juice a day to prevent UTIs in pregnancy and there seems to be plenty of evidence to back that up :D good luck

A glass a day? No hardship there, love the stuff. Thanks!

Reviving an old thread, sorry! But I've been put on antibiotics for nitrites as well (18wks) and this is the first time anyone tested my urine. Like OP no symptoms and they're still running tests to find out if anything definite.

Digging around here it seems they should have been testing for it since my booking appointment but no one ever asked for a sample until now, not the MW nor the consultant (high risk for BMI) - should I be worried?