Amniotic fluid arborization in the diagnosis of previable preterm premature rupture of membranes.

OBJECTIVE: To determine the accuracy of using amniotic fluid arborization to diagnose preterm premature rupture of membranes (PPROM) in the second trimester using specimens collected from the vaginal pool.

STUDY DESIGN: Women presenting for pregnancy termination between 14 and 22 weeks' gestation were enrolled. At the time of termination, amniotic fluid samples were collected directly from the amniotic sac and from the vaginal pool, air dried and examined for arborization.

RESULTS: Arborization was detected in 51/59 (86.4%) samples collected from the amniotic sac and 41/59 (69.5%) samples collected from the vaginal pool. The sensitivity and specificity in detecting arborization in fluid collected by swabbing the vagina was 0.69 and 0.98, respectively (positive predictive value 0.98%, negative predictive value 0.76).

CONCLUSION: While the presence of arborization in samples collected from the vaginal pool is predictive of PPROM in the second trimester, the absence of arborization should not rule out the diagnosis if there is strong clinical suspicion.