AmniSure Addresses an Unmet Need
Scope of the Problem
About one in five women will present during pregnancy with suspicion of PROM.1 One of the most common complications in pregnancy, PROM occurs in 5-45% of all pregnancies.2 PROM is responsible for 25-30% of all preterm births,3 which leads to an annual cost of ~$26 billion to the US healthcare system.4 At least 60% of cases occur in term patients.5 PPROM complicates 2-20% of all pregnancies.6 PPROM accounts for 20-40% of PROM7 and is the leading identifiable cause of premature birth, accounting for 18% to 20% of perinatal deaths in the US.8,9
For each patient presenting with suspicion of PROM, the risk of prematurity must be weighed against the risk of infection. A missed diagnosis can result in serious complications, such as cord prolapse, chorioamnionitis or neonatal sepsis. On the other hand, a false-positive PROM diagnosis can lead to unnecessary obstetrical interventions including admission, administration of medications and even induction. A timely and accurate diagnosis of PROM allows for salutary obstetrical interventions that optimize perinatal outcomes and minimize complications.
Inadequacy of Traditional Testing Methods
Traditional methods for diagnosing PROM include pooling, nitrazine/pH, ferning and ultrasound. The "Gold Standard" as deemed by the American College of Obstetrics and Gynecology is intra-amniotic injection of indigo carmine dye via amniocentesis. This method is used very infrequently, however, as it is an invasive procedure with inherent risks including placental abruption, infection, iatrogenic PROM and even miscarriage. Due to the limitations of the testing methods described in Table 1, there is an urgent need for an alternative, rapid, reliable and non-invasive method for diagnosing PROM.
|Pooling||Visualization of a vaginal pool in the posterior fornix of the vagina.||Inaccurate||Requires speculum examination. Subjective. Urine semen and other fluids can easily be mistaken for amniotic fluid or vice versa.|
|Nitrazine/pH Test||Amniotic fluid is alkaline, and as such, turns Nitrazine pH indicator blue.||Sensitivity: 90.7% Specificity:77.2%||Speculum exam is required to collect sample. False-positive results may be caused by cervicitis, vaginitis, alkaline urine, blood, semen, or antiseptics.|
|Ferning||Arborization pattern (crystallization) of dry amniotic fluid as seen through a microscope.||Sensitivity: 98.0%(labor)/ 51.4%(no labor) Specificity:88.2%(labor) and 79.8%(no labor)||Speculum exam is required to collect sample. Requires microscope. False positives may result from contamination of slide with fingertips or contamination with semen or cervical mucus. False negatives may be caused by dry swabs or contamination with blood and discharge.|
|Ultrasound||Ultrasound can detect oligohydramnios, suggesting loss of amniotic fluid due to membrane rupture.||Not a reliable screening test if used alone. Used only to confirm diagnosis.||Time-consuming. Requires U/S equipment and expertise. Can only detect significant loss of amniotic fluid. Cannot confirm fluid loss|
|Amnio-dye infusion||Instillation of dilute indigo carmine into amniotic cavity and confirmation of rupture of membranes by documenting leakage of dye into the vagina (staining of tampon) within 20-30 minutes.||ACOG's "Gold Standard" for diagnosis of ruptured fetal membranes.||Accurate, but highly invasive (requires amniocentesis). Expensive. Amniocentesis is associated with risk to pregnancy including bleeding, infection, iatrogenic rupture of membranes, and loss of pregnancy(approximately 1 in 270).|
|AmniSure ROM Test||Detection of a protein marker, PAMG-1, specific to amniotic fluid and virtually absent in semen, urine, blood, and vaginal discharge.||Sensitivity: 98.9% Specificity: 98.1%||Can provide unexpected positive in blood admixtures of 50% or more.|