The clinical significance of a positive Amnisure test in women with preterm labor and intact membranes

Objective: This study was conducted to examine the frequency and clinical significance of a positive Amnisure test in patients with preterm labor and intact membranes by sterile speculum exam. Study design: A retrospective cohort study was performed including 90 patients with preterm labor and intact membranes who underwent Amnisure tests prior to amniocentesis (< 72 h); most patients (n = 64) also underwent fetal fibronectin (fFN) tests. Amniotic fluid (AF) was cultured for aerobic/anaerobic bacteria and genital mycoplasmas and assayed for matrix metalloproteinase-8. Results: (1) the prevalence of a positive Amnisure test was 19% (17/90); (2) patients with a positive Amnisure test had significantly higher rates of adverse pregnancy and neonatal outcomes (e.g., impending preterm delivery, intra-amniotic infection/inflammation, and neonatal morbidity) than those with a negative Amnisure test; (3) a positive test was associated with significantly increased risk of intra-amniotic infection and/or inflammation, delivery within 7, 14, or 28 days and spontaneous preterm birth (< 35 weeks) among patients with a negative fFN test. Conclusions: A positive Amnisure test in patients with preterm labor and intact membranes is a risk factor for adverse pregnancy outcome, particularly in patients with a negative fFN test. A positive Amnisure test in patients without symptoms or signs of ROM should not be taken as an indicator that membranes have ruptured.