Vaginal fluid creatinine as a promising alternative to existing diagnostic test for premature rupture of membranes: Study
Premature rupture of membranes (PROM) refers “to the spontaneous rupture of the amniotic sac prior to the start of labor. When PROM occurs before 37 weeks of gestation, it is classified as preterm PROM, which can lead to complications such as preterm birth and chorioamnionitis”.
The risk of infection for both the mother and the fetus increases as the time duration between the rupture of membranes and the onset of labor time increases.
Detecting membrane rupture early and accurately is primal for providing appropriate care based on the baby's gestational age, which helps improve outcomes and reduce complications. Testing for creatinine in vaginal fluid can help diagnose PROM (as fetal urine), a main constituent of amniotic fluid (AF) in the latter half of pregnancy duration, contains creatinine. Since there isn't a definitive diagnostic method, various approaches using biochemical markers have been developed. Normally, the vagina does not contain creatinine, so its presence indicates membrane rupture. The level of creatinine in AF rises significantly between the 20th and 32nd weeks of pregnancy, reaching levels 2-4 times higher than in the mother's blood.
The women admitted between 28 to 37 weeks of pregnancy fulfilling inclusion and exclusion criteria were enrolled in our study after their informed consent. They were categorised as group 1 (cases) and group 2 (controls) (n=140 each, on the basis of history of leaking per vaginum). They were investigated by doing relevant investigations and clinical examination. Vaginal fluid was collected & sent to Department of Biochemistry for creatinine estimation. All patients participating in this study were followed till delivery to record maternal and fetal outcomes
Parametres such as age, parity, BMI, gestation age, occupation and social background did not show any statistical significance among cases and controls. Cases had significantly higher creatinine levels in vaginal fluid & lower Amniotic fluid index (AFI) as those in controls. Cases had higher risk of chorioamnionitis, prolonged hospital stay & surgical site infections. Neonatal Intensive care unit (NICU) admission and still births were significantly higher in cases than controls.
An appropriate and correct diagnosis of PROM is important for a successful pregnancy. This study revealed that PROM is a common pregnancy issue that causes increased maternal and neonatal difficulties such as surgical procedures, neonatal morbidity, and mortality. Detection of vaginal fluid creatinine to identify PROM is a simple, quick, and reliable test with good sensitivity, specificity, PPV, NPV, and overall accuracy. Diagnosis of PROM is challenging with existing procedures in equivocal cases, thus incorporating this method into everyday use is feasible and practical because there is no need for additional equipment or reagents. It may be made available in low-resource communities and is cost-effective for detecting PROM. Additionally, investigations with larger sample size might aid in identifying the greater application of this marker in the diagnosis of PROM.
Source: Singh et al. / Indian Journal of Obstetrics and Gynecology Research 2025;12(2):229–234
