Placental alpha-microglobulin-1 in cervico-vaginal fluid predicts preterm birth in women with preterm labor and intact membranes

Abstract

Introduction: Preterm birth is a major cause of neonatal morbidity and mortality in developed countries. The placental alpha-microglobulin-1 (PAMG-1) is a protein that can be found in high concentrations in the amniotic fluid and in lower concentrations in the vaginal secretion in patients with signs of preterm labor without rupture of membranes. We aimed to evaluate PAMG-1 diagnostic kit in the prediction of preterm birth. Material and methods: We included 119 patients (between 24 0/7 and 36 6/7 gestational weeks) in this prospective observational trial. We included patients with symptoms of preterm labor and gestational age-matched controls. We evaluated the sensitivity (SN), specificity (SP), positive predictive value (PPV) and negative predictive value (NPV) of PAMG-1 measurements compared to transvaginal cervical length (CL) measurements. The performance of the test was calculated within 48 hours, 7 days and 14 days. We performed a subgroup analysis in symptomatic patients with CL between 15 and 30 mm. Results: We detected superior SP and PPV in the PAMG-1 compared to CL group at all time points. SN was higher in the CL group and NPV was similar in both groups. PAMG-1 performance was confirmed within the subgroup (CL: 15 – 30 mm) of symptomatic patients, where CL measurements are at least accurate predicting preterm birth. Conclusions: The novel PAMG-1 test has a high PPV and SP compared to other commercially available bed-side tests. Our study suggests clinical usefulness of the PAMG-1 test, especially in addition to cervix length measurements. Its utilization may reduce unnecessary hospitalizations and overtreatment.