Combined value of placental alpha microglobulin‐1 detection and cervical length via transvaginal ultrasound in the diagnosis of preterm labor in symptomatic patients

AIM We aimed to evaluate the combined value of placental alpha microglobulin-1 (PAMG-1) and cervical length (CL) via transvaginal ultrasound for assessing risk of imminent spontaneous preterm delivery in patients presenting with threatened preterm labor (PTL). METHODS Clinical exam, PAMG-1 test, cardiotocography, and CL measurement via transvaginal ultrasound were performed on all patients meeting inclusion criteria. Ninety-nine patients at 22+0 -36+6 gestational weeks with the symptoms of PTL were included. The interval between sample collection and delivery was measured for each method. RESULTS Performance metrics were calculated for PAMG-1 test, CL < 25 mm, and contractions ≥ 8/h. The sensitivity, specificity, positive predictive value, and negative predictive value for the PAMG-1 test were 100%, 95%, 75%, 100% and 100%, 98%, 88%, 100% for 7 and 14 days, respectively; the respective values for CL < 25 mm were 83%, 59%, 22%, 96% and 79%, 59%, 24%, 94% for 7 and 14 days; and those for contractions ≥ 8/h were 42%, 38%, 8%, 83% and 43%, 38%, 10%, 80% for 7 and 14 days. Specificity for the PAMG-1 test was statistically significant (P < 0.001) in pairwise comparisons for all other methods. Patients were divided into four groups for analysis of PAMG-1 test performance as follows: CL < 15 mm (100%, 100%, 100%, 100% and 100%, 100%, 100%, 100% for 7 and 14 days, respectively); CL < 25 mm (100%, 94%, 83%, 100% and 100%, 97%, 92%, 100% for 7 and 14 days, respectively); CL of 15-30 mm (100%, 95%, 64%, 100% and 100%, 97%, 82%, 100% for 7 and 14 days, respectively); and CL ≥ 30 mm (100%, 100%, 100%, 100% and 100%, 100%, 100%, 100% for 7 and 14 days, respectively). CONCLUSION The use of the PAMG-1 test in patients with a CL of 15-30 mm is highly predictive of imminent spontaneous preterm delivery in women presenting with threatened PTL and could save hospital resources.