Noticed “leukocytes” flagged in your urine report during ANC and felt your mind go straight to infection? That reaction is common. In many Indian labs, urine testing is frequent, and one abnormal line can look scary without context. Leukocyturia during pregnancy simply means white blood cells are present in urine. Sometimes it points to a urinary tract infection. Sometimes it is just a contaminated sample (easy when vaginal discharge is heavier in pregnancy). And sometimes it reflects irritation or inflammation without bacteria.
The safest approach is practical: confirm with a properly collected sample, check for symptoms, and rely on urine culture before starting treatment, because antibiotics in pregnancy should be chosen carefully.
What leukocyturia means during pregnancy
A simple definition: white blood cells in urine
Leukocyturia during pregnancy means white blood cells (leukocytes) are detected in urine. White blood cells are immune cells, they appear when the body responds to inflammation somewhere along the urinary tract (urethra, bladder, ureters, kidneys).
This often suggests a urinary infection, but it is not automatic. Leukocyturia during pregnancy can also come from:
- non-infectious irritation (including mechanical pressure)
- inflammation around the vulva or vagina
- contamination of the urine sample by vaginal secretions
Many laboratories call leukocyturia “significant” from around ≥ 10^4 leukocytes/mL (thresholds vary by method). Some reports use microscopy and list WBC/HPF (white blood cells per high-power field).
“Septic”, “aseptic”, or “isolated” leukocyturia: what these labels usually mean
These terms mainly describe whether bacteria are found along with leukocytes:
- Septic leukocyturia: raised leukocytes plus bacteriuria confirmed on urine culture, strongly suggests a UTI.
- Aseptic leukocyturia (sterile pyuria): leukocytes present but culture negative/very low, common reasons are contamination, inflammation, stones, or organisms not detected by routine culture.
- Isolated leukocyturia: leukocytes reported without confirmed bacteriuria, in pregnancy, repeating a well-collected sample is often the next step.
Leukocyturia vs pyuria: dipstick and microscopy
Dipstick leukocyte esterase: helpful, but not a diagnosis
Dipsticks look for leukocyte esterase, an enzyme linked to white blood cells. It is a helpful screening clue, but it does not prove infection. False positives are common, especially when the urine sample is contaminated by vaginal discharge.
Microscopy: WBC/HPF and contamination clues
Microscopy counts cells directly (often as WBC/HPF) and may also show contamination clues, such as many epithelial cells. If results don’t match how you feel, repeating the test with careful collection can make interpretation much clearer.
Why leukocyturia is more common during pregnancy
Pregnancy changes the urinary tract in ways that increase inflammation and infection risk:
- Progesterone relaxes smooth muscle, leading to dilation and slower urine flow.
- The growing uterus can compress the bladder and ureters.
- Urinary stasis increases, meaning urine sits longer and the natural “flushing” effect is reduced.
Because of these changes, bacteria can settle more easily, and some infections stay subtle, or silent, while still having the potential to ascend towards the kidneys.
Common causes of leukocyturia in pregnancy
Urinary tract infection: cystitis and pyelonephritis
A common cause, especially with symptoms, is a UTI:
- Cystitis: lower UTI affecting the bladder.
- Pyelonephritis: upper UTI affecting the kidneys.
The most frequent organism is Escherichia coli, though others can be responsible. During pregnancy, UTIs are treated promptly to reduce the chance of spread to the kidneys.
Asymptomatic bacteriuria: bacteria without urinary symptoms
You can have bacteria on urine culture without burning or discomfort. This is asymptomatic bacteriuria, and it is specifically screened for in pregnancy.
Why treat if you feel fine? Because asymptomatic bacteriuria increases the risk of pyelonephritis and is linked with obstetric complications. Treating it reduces those risks.
Leukocyturia with a negative culture (sterile pyuria): frequent explanations
When leukocytes are present but routine culture is negative, possibilities include:
- Vaginal contamination of the urine sample (common and often benign)
- Local inflammation (vulvar/vaginal inflammation) that can “spill” cells into the sample
- A urinary stone causing mechanical irritation (sometimes one-sided back pain)
- Infections not detected on standard culture that may need targeted tests depending on context (for example chlamydia, mycoplasma, ureaplasma)
Symptoms to watch: how to recognise a UTI in pregnancy
No symptoms: yes, it can happen
Leukocyturia during pregnancy is sometimes found on routine testing when you feel well. In pregnancy, common explanations are:
- asymptomatic bacteriuria (confirmed by culture), or
- contamination or non-infectious inflammation.
That is why a dipstick alone is not enough to conclude infection, clinical context and culture guide next steps.
Cystitis symptoms: burning, urgency, pelvic discomfort
Typical bladder infection symptoms:
- burning or pain with urination (dysuria)
- frequent urination in small volumes (frequency), sometimes urgency
- suprapubic heaviness or discomfort
- sometimes blood in urine
Pregnancy can already cause frequent urination. A helpful question is: “Is this new, painful, and associated with irritation?” If yes, call your maternity team.
Pyelonephritis symptoms: fever plus flank/back pain
Pyelonephritis in pregnancy needs rapid assessment. Typical signs:
- fever (often ≥ 38°C / 100.4°F) with chills
- flank or back pain
- nausea or vomiting
- marked fatigue and feeling unwell
Fever with flank/back pain is a reason to seek care without delay.
Tests used in pregnancy: dipstick, urinalysis, and culture
Dipstick nitrites: how to read them
Dipsticks also test nitrites, produced by some bacteria (commonly gram-negative bacteria such as E. coli).
- Leukocytes plus nitrites: strong suspicion of bacterial UTI.
- Nitrites negative: does not rule out infection (not all bacteria produce nitrites, urine needs to stay in the bladder for several hours, vitamin C can interfere).
- Leukocytes alone: contamination is common in pregnancy, so confirmation is important.
Urine culture: the reference test
A urine culture identifies:
- the level of bacteriuria,
- the organism,
- and the antibiogram (antibiotic sensitivity).
Sample quality directly affects results, so collection matters.
How to collect a clean-catch midstream sample
A reliable sample often includes:
- washing hands
- gentle cleaning of the vulva with water (or mild soap if advised)
- letting the first part of urine go into the toilet
- collecting midstream urine into a sterile container without touching the inside
- closing promptly and transporting to the lab quickly
Interpreting leukocyturia in context: what usually happens next
Isolated leukocyturia: repeat testing is often the safest next step
Isolated leukocyturia during pregnancy is frequently due to imperfect collection. Before treating, your care team may advise repeating urinalysis and culture, especially if:
- you have no urinary symptoms
- the culture is negative
- this is a first episode
This avoids unnecessary antibiotics while keeping monitoring safe.
Leukocyturia plus urinary symptoms: cystitis is likely
When leukocyturia during pregnancy occurs with burning and urgency, cystitis is a likely explanation. Treatment may start quickly, then be adjusted once culture/antibiogram results return. In pregnancy, stopping an infection early helps prevent ascent to the kidneys.
Leukocyturia plus fever or flank pain: urgent evaluation
Fever and flank/back pain with leukocyturia should be treated as a priority, because kidney infection can worsen quickly during pregnancy.
Treatment and follow-up during pregnancy
Confirm when possible, then choose a pregnancy-compatible antibiotic
Whenever possible, treatment is guided by culture and antibiogram, using antibiotics compatible with pregnancy. The goal is effective treatment with the most targeted option.
Cystitis and asymptomatic bacteriuria: treat, then recheck
In pregnancy, the principle is to clear confirmed infection even when symptoms are absent, to reduce pyelonephritis risk.
Depending on gestational age, organism, allergies, and local recommendations, commonly used options include:
- fosfomycin trometamol (often single dose for uncomplicated cystitis)
- oral cephalosporins
- amoxicillin when susceptible
- nitrofurantoin in certain situations (typically lower UTI, with timing precautions)
A follow-up urine culture is often recommended 1-2 weeks after finishing treatment, especially after asymptomatic bacteriuria, recurrent infections, or persistent symptoms.
Pyelonephritis: more intensive care is often needed
For pyelonephritis, teams often recommend:
- hospital admission at least initially
- IV antibiotics followed by oral antibiotics
- monitoring hydration, temperature, pain, and pregnancy wellbeing
If recovery is slow, clinicians may look for a contributing factor such as a stone or obstruction.
Risks, prevention, and when to seek urgent care
Why clinicians take leukocyturia seriously in pregnancy
An untreated urinary infection can progress to:
- pyelonephritis
- maternal sepsis
- increased risk of premature rupture of membranes
- association with preterm birth and fetal growth restriction in infection-related cases
This is why Leukocyturia during pregnancy is evaluated carefully, even when it looks “small” on paper.
Everyday prevention habits that can help
Helpful habits include:
- drinking water regularly (unless fluid restriction was advised)
- passing urine when you feel the need (avoid holding)
- passing urine after intercourse if you are prone to cystitis
- gentle external hygiene (avoid internal cleansing)
- managing constipation, which can worsen pelvic pressure and urinary stasis
If UTIs repeat, your care team may suggest closer urine monitoring through the rest of pregnancy.
When to contact your care team urgently
Seek prompt assessment if you develop:
- fever ≥ 38°C / 100.4°F, chills
- flank/back pain, especially with fever
- vomiting, severe weakness, dehydration signs
- regular contractions, unusual abdominal pain, fluid leakage
- decreased fetal movements
- intense urinary symptoms or symptoms persisting despite initial measures
À retenir
- Leukocyturia during pregnancy means white blood cells in urine, it can reflect infection, inflammation, stones, or sample contamination.
- Pregnancy increases urinary stasis and UTI risk, sometimes without symptoms.
- Dipsticks help screen, but a urine culture with antibiogram confirms and guides treatment.
- Asymptomatic bacteriuria is treated during pregnancy to reduce pyelonephritis risk.
- Fever, flank/back pain, vomiting, contractions, fluid leakage, or decreased fetal movements require rapid evaluation.
- There are clinicians and maternity services to support you, and you can download the Heloa app for personalised guidance and free child health questionnaires.
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