When it happens · 3 min read
UTIs in pregnancy, and why they test your urine every time
The cup at every appointment isn't only about protein and preeclampsia. It's also looking for bacteria — including in people who feel completely fine, which is a rule specific to pregnancy.
Last updated August 9, 2026
Why silent bacteria get treated
Outside pregnancy, bacteria in the urine without symptoms usually need no treatment. In pregnancy that changes: a relaxed, dilated urinary tract and a compressing uterus make it far likelier that bacteria travel upward to the kidneys. Untreated asymptomatic bacteriuria progresses to pyelonephritis in a substantial minority of cases, and pyelonephritis in pregnancy is associated with preterm labor, sepsis, and serious illness.
So screening with a urine culture is recommended prenatal care, and a positive result gets antibiotics even when you feel entirely well. That's not over-treatment; it's the one context where the calculus genuinely flips.
Bladder infection symptoms
Burning or stinging when you urinate. Needing to go constantly, or urgently, and producing little. Cloudy, strong-smelling, or blood-tinged urine. Low pelvic discomfort. Some of this overlaps with ordinary pregnancy — frequency in particular — so the distinguishing features are burning and urgency rather than volume.
Call the same day. Treatment is a course of a pregnancy-safe antibiotic, and finishing it matters even once symptoms clear, since stopping early is what lets the infection re-establish.
The kidney version
Fever and chills, pain in your back or side (usually one side, around the lower ribs), nausea and vomiting, feeling genuinely unwell. That's pyelonephritis and it needs urgent assessment — often IV antibiotics and sometimes admission, because in pregnancy it can escalate quickly and can trigger preterm contractions.
Reducing the odds
Drink enough that your urine stays pale. Don't hold it. Urinate after sex. Wipe front to back. None of these are guarantees — plenty of people do everything right and still get one — and none of them substitute for treating a positive culture.
Common questions
- I have no symptoms but they found bacteria. Do I really need antibiotics?
- In pregnancy, yes — this is the specific situation where treating silent bacteria is recommended, precisely because of how often it would otherwise progress.
- Is cranberry enough?
- No. It's harmless and the evidence for prevention is weak; it does not treat an established infection, and in pregnancy an untreated one is the thing to avoid.
- Can a UTI cause contractions?
- Infection — particularly a kidney infection — can trigger preterm contractions, which is one of the main reasons this gets treated promptly.
If it's this, not that
Still not sure
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Where this comes from
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