Detection of pregnancy using dielectric properties of urine

This article investigated and compared the dielectric properties of urine between pregnant women and non-pregnant women. Urine samples were collected from 30 pregnant women and 30 non-pregnant women. Dielectric properties of the urine were measured between 0.2 and 50 GHz at temperatures of 25, 30 and 37 °C. The composition of urine and human chorionic gonadotropin (hCG) were also determined accordingly. The urine of pregnant women was observed to have statistically significant lower dielectric constant than that of non-pregnant women at three temperatures and at certain frequencies (p < .05, mean relative error <0.48%). Loss factor (p < .05, mean relative error < .56%) and loss tangent (p < .05, mean relative error <0.71%) were statistically significant higher in pregnant women than that in non-pregnant women at three temperatures and at certain frequencies. The dielectric properties decreased with temperature before the crossing point while they increased with temperature after the crossing point. In general, the dielectric properties correlated positively with hCG at low frequencies but they correlated negatively with hCG at high frequencies. The correlation coefficients of more than ±0.85 indicated strong correlation, which suggested potential development of a diagnostic tool for pregnancy using the dielectric properties of urine.