Urinalysis is a part of the routine prenatal tests to diagnose any medical condition during pregnancy, including kidney infections, preeclampsia, and gestational diabetes. It also detects the increase of leukocytes in urine during pregnancy, which may indicate the presence of any infection or inflammation of the genitourinary or urinary tract. You may also need the urinary test to check the functioning of the maternal organs (1) (2).
Read on to know the causes, risk factors, symptoms, diagnosis, treatment management, and preventive measures for leukocytes or white blood cells (WBCs) in urine when pregnant.
What Are Leukocytes In Urine?
Leukocytes or WBCs are a part of your immune system and include granulocytes (neutrophils, eosinophils, and basophils), monocytes, and lymphocytes (T cells and B cells). Together, these WBCs help the body fight infections and other diseases.
In general, measuring the leukocyte count is a part of a complete blood cell count (CBC) test (3). However, if urinary tract infections (UTIs) or inflammation are suspected, your health care provider may suggest a urine test to detect the presence of leukocytes (particularly neutrophils). Normally, urine is sterile, so the normal range of leukocytes in urine is low, i.e., up to 5 WBCs per high power field (WBC/HPF) (4).
Causes Of Leukocytes In Urine During Pregnancy
During pregnancy, elevated levels of leukocytes in urine may occur due to various infections, including
- Urinary tract infection: Its probability increases by 8% during pregnancy, and it is mostly caused by Escherichia coli. The decreased ability of the lower urinary tract to resist invading bacteria during pregnancy contributes to the development of UTIs in pregnancy. Subsequently, the leukocyte count in urine increases to fight off this infection (5).
- Asymptomatic bacteriuria: This UTI causes a bacterial infection without any symptoms, causing leukocytes to appear in the urine. Untreated asymptomatic bacteriuria can lead to pyelonephritis (kidney infection) and affect the fetus.
Therefore, it is recommended to do repeated urine culture or urine dipstick leukocyte esterase tests (a faster screening method) during pregnancy to measure the leukocyte level (6).
- Genital infections: Certain genital infections, including bacterial vaginosis, vaginitis, and vaginal yeast infection, are common during pregnancy. They are mainly caused by hormonal changes and can lead to pyuria (causing leukocytes in urine) (6) (7).
- Pyelonephritis: It may develop when a UTI or asymptomatic bacteriuria is untreated during pregnancy. It is a severe systemic kidney infection that can cause high amounts of leukocytes in the urine and have negative pregnancy outcomes (5) (6) (8).
- Cystitis (bladder inflammation): This UTI affects around 1% of all pregnancies. It is differentiated from asymptomatic bacteriuria by symptoms such as dysuria, urine urgency or frequency, and suprapubic pain (pain in the lower abdomen) without evidence of systemic illness. Since it causes elevated WBC levels in the urine, a urinalysis is used to diagnose it in pregnancy (9) (10).
- Trichomoniasis: Although uncommon in pregnancy, this sexually transmitted infection (STI) may cause excess WBCs in the urine due to inflammation (11) (12).
Symptoms Of White Blood Cells In Urine When Pregnant
- Dysuria (pain or burning while urinating)
- Frequent urination
- Urine urgency
- Suprapubic pain
- Foul-smelling urine
- Flank pain or renal angle (lower back) pain
- Fever (pyrexia)
- Nausea and vomiting
Diagnosis Of Leukocytes In Urine During Pregnancy
The following diagnostic methods can be used to detect leukocytes in urine (14):
- Leukocyte esterase urine dipstick test: Increased WBCs or leukocytes in the urine sample of a pregnant woman can be diagnosed using a leukocyte esterase urine dipstick test. The procedure includes (1) (15) (16)
- Collection of the urine sample: Generally, a clean-catch urine sample is recommended. Your doctor may provide a clean-catch kit with a washing solution and sterile wipes, or you may be asked to collect a small sample of clean, midstream urine in a sterile plastic cup.
- Urine dipstick test: Your health care provider may test the sample right after the urine sample collection. Chemically prepared testing strips of leukocyte esterase with a color-sensitive pad are dipped into your urine sample to screen for indicators such as leukocytes.
- Positive test: If the strip changes color within 30 seconds to two minutes (depending on the brand), it is taken as a positive test, suggesting infection or inflammation in the urinary tract.
- Negative test: If the strips show no color change, your urine sample may not have a significant amount of leukocytes. However, high protein and vitamin C levels in the urine or specimen contamination with vaginal secretions may interfere with the result. In such cases, your doctor may recommend a urine culture if you have other symptoms suggestive of UTI.
- Microscopic urinalysis: If your leukocyte esterase urine dipstick test is positive, a microscopic examination of the urine and urine culture and sensitivity are performed to determine the WBC level and check for indicators of infection.
The urine sediment of a fresh urine sample is centrifuged at 1,500 to 3,000 rpm for five minutes and resuspended in the remaining liquid for analysis. A single drop is deposited on a clean glass slide, covered with a coverslip, and viewed under a microscope.
- Urinary leukocyte cast: They can be used to identify the location of the illness in the genitourinary tract.
Treatment Of Elevated White Blood Cells In Urine During Pregnancy
The treatment options may vary depending on the cause and elevation level of leukocytes in the urine. Some common treatment methods to balance or decrease the levels of leukocytes in urine during pregnancy are (10)
- Antibiotic therapy: Almost all the conditions causing elevated leukocytes in urine during pregnancy can be managed with appropriate antibiotic treatment. However, certain antibiotics, such as fluoroquinolones, are contraindicated during pregnancy. Hence, ask your doctor before taking any antibiotics (17).
- Natural remedies: Consumption of cranberries, garlic, probiotics, parsley, L-arginine supplements, and sufficient water can help treat UTI and other urinary tract infections during pregnancy (18).
Complications Of Elevated White Blood Cells In Urine During Pregnancy
Treatment should be initiated soon after a high level of leukocytes is detected in urine samples to prevent adverse obstetrical outcomes. Some of the maternal complications include (10)
- Preterm delivery
- Maternal sepsis
- Chorioamnionitis (bacterial infection in the membranes surrounding the fetus)
- Postpartum endometritis
It can also cause the following complications in the fetus (10):
- Low birth weight
- Premature birth
- Growth restriction
- Perinatal mortality
- Mental retardation
- Developmental delay
Prevention Of Elevated White Blood Cells In Urine During Pregnancy
- Do regular urine tests to prevent recurrent infections (10)
- Drink plenty of water
- Consume cranberry juice and supplements
- Maintain good hygiene practices, such as wiping from front to back after a bowel movement
- Avoid synthetic and tight-fitting lingerie
- Avoid perfumed genital washing gels
Frequently Asked Questions
1. Can I have leukocytes in urine without infection?
Yes. Normally, you may have 0–5 WBC/HPF in your urine even when pregnant. However, if the level exceeds 5 WBC/HPF, it may be a sign of infection or inflammation in the urinary tract, and treatment may be required (4).
2. Can leukocytes in urine cause fetal death if left untreated?
Yes. Other than UTI, increased leukocytes in the urine of a pregnant woman may be due to cystitis, pyelonephritis, or various genital infections, which increase the risk of a fatal complication in the fetus. However, fetal death is rare in such cases (10).
Urine samples may show elevated leukocytes during prenatal urine tests, indicating urinary tract infection or inflammation. It could be caused by disorders such as UTI, asymptomatic bacteriuria, genital infection, pyelonephritis, or trichomoniasis with symptoms such as urinary urgency, foul-smelling urine, and fever. If you notice any of these symptoms, consult your doctor for a proper diagnosis and treatment.
- Getting a Pregnancy Urinalysis: About Prenatal Urine Tests.
- Microscopic Urinalysis.
- Karen M. Ringsrud; (2001); Cells in the Urine Sediment.
- John E. Delzell J. R. and Michael L. Lefevre; (2000); Urinary Tract Infections During Pregnancy.
- Richard Colgan et al.; (2006); Asymptomatic Bacteriuria in Adults.
- Female Genital Problems and Injuries.
- J. C. Dawkins et al.; (2012); Acute Pyelonephritis in Pregnancy: A Retrospective Descriptive Hospital Based-Study.
- Interstitial Cystitis.
- Timothy McCormick et al.; (2008); Review Urinary tract infection in pregnancy.
- Leukocyte esterase urine test.
- Urinary Tract Infections.
- Jeff A. Somerville et al.; (2005); Urinalysis: A Comprehensive Review.
- Leukocyte esterase urine test.
- Patricia J. Habak and Robert P. Griggs Jr.; (2021); Urinary Tract Infection In Pregnancy.
- Anthony Mansour et al.; (2014); Efficient and Cost-Effective Alternative Treatment for Recurrent Urinary Tract Infections and Interstitial Cystitis in Women: A Two-Case Report.