Assessment of Urea and Creatinine in Vaginal Washing Fluid as a Method for Diagnosis of Premature Rupture of Membranes

Abstract Background: Premature rupture of membranes (PROM) refers to rupture of fetal membranes prior the onset of labor. If it occurs before 37 weeks of pregnancy, it is known as preterm premature rupture of membrane (PPROM). Prolonged duration from PROM till delivery is associated with increased maternal and neonatal morbidities, in term and preterm preg-nancies. This includes chorioamnionitis, fetal and neonatal sepsis, placental abruption, prematurity, umbilical cord pro-lapse, and increased rate of cesarean delivery. Pregnant women with history of vaginal leaking or ultra-sound evidence of diminished amniotic fluid should be care-fully evaluated to avoid adverse pregnancy outcomes. Accurate diagnosis helps obstetricians to optimize maternal and neonatal outcomes by early intervention to decrease morbidities. Diagnosis of PROM is may be easy by inspection of leaking through the cervix or fluid accumulation via speculum examination. However, with small rupture of membrane or rupture bag of hind-water, it is difficult to see amniotic fluid leakage clearly and diagnosis can't be easily made, which might lead to delay in diagnosis and management. Methods of PPROM diagnosis include fern and nitrazine which are two commonly used and traditional tests. They are rapid and easy tests but not completely reliable because of high false positive and negative results, which may be related to technical errors or contamination by blood, semen or cervical mucus. Ultrasound evaluation of amniotic fluid can't differentiate PROM from other causes of oligohydramnios. However, tampon or amnio-dye test is a test of accurate diagnosis through aspiration and dye injection into amniotic fluid under ultrasound guidance. It is an aggressive test with has a risk of bleeding, placental abruption infection, miscarriage, and iatrogenic uterine perforation. The Amnisure test for ROM is accurate but expensive and not available in many centers. Thus, a simple, non-invasive, and inexpensive method of detecting PROM is needed. Urea and creatinine are excreted by kidneys through glomerular filtration. Amniotic fluid also contains these markers and their determination in the vaginal can be used as a diagnostic test for PROM.
Aim of Study: This study was conducted to evaluate the diagnostic value of urea and creatinine levels in vaginal wash in patients with suspected PROM. Patients and Method: The study was carried out at Ob-stetrics and Gynecology Department, Zagazig University Hospitals. A total of 228 pregnant women were included in study, between completed 24 weeks to completed 37 weeks' gestation. Divided into two equal groups: Group A with definite PROM, control Group is B. All pregnant women included in this study were subjected to: Full history taking, general, abdominal and speculum examination, fern test and nitrazine test. Vaginal wash urea measurement by enzymatic urease examination method and vaginal wash creatinine measurement by RATE JAFFE method. Results: The study showed that there is statistically significant difference between the two groups regarding vaginal wash urea and creatinine. The best cut-off value of vaginal wash urea in prediction of PROM is >!6.85mg/dl with AUC of 0.958, sensitivity of 98.2%, specificity of 70.2%, PPV of 76.7%, NPV of 97.6% and accuracy of 93%. The best cut-off value of vaginal wash creatinine in prediction of PROM is >!0.465mg/dl with AUC of 0.992, sensitivity of 100%, specificity of 80.7%, PPV of 83.8%, NPV of 100% and accuracy of 90.4%. Combined use of vaginal wash urea and creatinine in prediction of PROM had sensitivity of 98.3%, specificity of 91.2%, PPV of 91.8%, NPV of 98.1% and accuracy of 94.7%. Conclusion: This study concluded that urea and creatinine assay in vaginal fluid is cheaper, faster and more valid test, possible candidate for being a gold standard test for diagnosis of PROM.