Role of cervical length and placental alpha microglobulin-1 to predict preterm birth

Preterm labor is the leading cause of premature mortality and morbidity. Therefore, to rule-in and rule-out preterm delivery is a very important issue in our clinical practice.

The aim of this study was to investigate the value of placental alpha microglobulin-1 (PAMG-1) molecule positivity in cervicovaginal secretions of women who have a CL <25 mm and presenting with preterm labor symptoms to predict spontaneous preterm birth within seven days.

This was a prospective cohort study conducted in Ankara University Department of Obstetrics and Gynecology between August 2017 and February 2019 on the patients who had Preterm labor symptoms, <25 mm transvaginal cervical length (CL), clinically intact membranes. The primary outcome of the study was the power of CL and PAMG-1 positivity on the prediction of preterm birth in seven days.

Sensitivity and specificity values of PAMG-1 in our study population to predict spontaneous preterm birth in seven days were calculated 52.94% and 98.84%, respectively, negative predictive value (NPV) and positive predictive value (PPV) were calculated 91.4% and 90%, respectively. When we investigated our data according to different CL cutoffs, sensitivity and NPV for 20 mm cutoff were 88.24% and 96.3% that was better than PAMG-1, but specificity and PPV were 60.47% and 30.61%, respectively, that was more ineffective than PAMG-1. If we calculate the values according to 15 mm and 10 mm CL cutoffs sensitivity values were 58.8% and 23.53%, specificity values were 81.4% and 91.86%, NPV were 90.9% and 85.87%, PPV were 38.46% and 36.36%, respectively. Finally, accuracy value of PAMG-1 to predict spontaneous preterm birth in seven days was 91.26% that was better than other CL cutoffs (20 mm, 15 mm, and 10 mm).

PAMG-1 molecule with high NPV and PPV (91.4% and 90%) combination will contribute our clinical decision on the population who had preterm labor symptoms and a CL shorter than 25 mm.