Alternative Approach to Monitoring Labor: Purple Line

Abstract Background This study was conducted to evaluate the effectiveness of the purple line, a method for assessing labor progress. Methods Data for this methodological study were collected from 304 pregnant women who presented to a maternity hospital for delivery on the Anatolian side of Istanbul between May and November 2021. Data collection included demographic information, partograph records, and measurements of the purple line. Women were followed via the partograph during active labor, with the purple line measured hourly via a disposable tape measure until delivery. Descriptive analyses, including means and standard deviations, medians and interquartile ranges, and receiver operating characteristic (ROC) curves, were conducted for data analysis. Results The mean age of the participating women was 27.74 (4.81) years, with a mean parity of 1.92 (1.12) and a mean gestational age of 39.05 (1.59) weeks at delivery. The purple line was observed in 85.9% of the women. Among all the women with the most common dilatation of 6 cm during labor, 85.9% had a visible purple line, with a specificity of 86% and sensitivity of 65%. The cut-off point was determined to be 9.5 cm. During the active phase of labor, the measurements of the purple line length in the sacral region increased proportionally with cervical dilatation. The sensitivity was 56%, and the specificity was 65% when the fetal head descent reached the − 2 level. Conclusions In conclusion, the purple line in the sacral region can be used as a noninvasive method to assess the course of labor and can be applied in clinical settings.