Proposal of a diagnostic test for the detection of preterm premature rupture of membranes based on the determination of thyroid hormones in vaginal washing fluid

Abstract

Objectives: To determine whether measurement of total T3 (triiodothyronine) , total T4 (thyroxine), free T3 (free triiodothyronine) and free T4 (free thyroxine) levels in vaginal fluid is useful for the diagnosis of preterm premature rupture of membranes (PPROM).

Study design: The PPROM group and normal pregnancy group consisted of 30 and 30 pregnant patients between 26 and 36 weeks' gestation, respectively. Vaginal fluid total T4, free T4, total T3 and free T3 levels were measured in both groups.

Results: Vaginal fluid total T3 and free T3 levels were not statistically significant in the PPROM group as compared with the control group (p = 0.087, p = 0.123, respectively). Vaginal fluid total T4 and free T4 levels were significantly higher in the PPROM group as compared with the control group (p = 0.002, p < 0.000, respectively). The optimal cut-off value for total T4 (0.866 mug/dl) gave a sensitivity level of 83.3% (65.3-94.3, 95% CI) at a specificity of 60.0% (40.6-77.3, 95% CI) with positive and negative predictive values of 67.6 and 78.3%, respectively. The optimal cut-off value for free T4 (0.079 ng/dl) gave a sensitivity level of 90% (73.4-97.8, 95% CI) at a specificity of 70.0% (50.6-85.2, 95% CI) with positive and negative predictive values of 75.0 and 87.5%, respectively.

Conclusions: Total and free T4 measurements from vaginal fluids appears to be a useful marker of PPROM.