Premature Amniotic Fluid Rupture
Leaking amniotic fluid during any stage of pregnancy is caused by a rupture of the amniotic sac. While this is a normal part of labor, serious health complications can result when it occurs pre-term. Early rupture of the amniotic sac falls into one of two categories:
- Premature rupture of membranes (PROM) is a premature rupture of the amniotic sac occurring after 37 weeks gestation
- Preterm premature rupture of membranes (pPROM) is any premature amniotic sac rupture occurring earlier than 37 weeks gestation
PROM is one of the most common complications in pregnancy, occurring in an estimated 8-10% of all births.1 Most often, the best way to manage late-term PROM is simply to induce labor. In cases where this is not possible, the supervising obstetrician may recommend one of several management options, such as bed rest, antibiotics or corticosteroids.
pPROM is a more serious condition which can result in potentially severe complications, including infection, placental abruption and umbilical cord prolapse. pPROM is implicated in an estimated 18-20% of all perinatal deaths.1 pPROM is also expensive and remains an important perinatal dilemma as the clinician attempts to balance the risk of prolonging gestation against the risks of infection.2
Diagnosing PROM and pPROM
For these reasons, early detection and intervention is critical in cases of premature rupture of fetal membranes. In many incidences of PROM, amniotic fluid pooling may be visible during a physical examination. However, this alone is not enough to make a confident diagnosis of PROM or pPROM. This is partially due to the imprecision and subjectivity of visual speculum examination, and also in 47% of ROM cases, obvious leakage from the cervical os is not evident/visible by the naked eye. 3
Beyond the Gold Standard of Testing
A current gold standard of testing for premature fetal membrane rupture is the intra-amniotic transabdominal instillation of indigo carmine. This ROM test is highly invasive and expensive. It requires sophisticated equipment that many birth centers do not possess and is rarely used due to its invasiveness.
In recent years, however, several easy-to-administer tests have become available. The most reliable, according to a number of studies and guidelines,4,5 identifies the presence of the placental alpha microglobulin (PAMG-1) protein, a biomarker that is found in high concentrations in amniotic fluid and in low concentrations in cervicovaginal discharge.
Currently, AmniSure® is the only commercially available test for PAMG-1 compared to the indigo carmine test; the published study demonstrated that AmniSure has a ~99% correlation with the indigo carmine test. Thus, AmniSure provides accuracy, ease of use, and reliability without the need for the invasive procedures and risks associated with the indigo carmine test.
- Caughey, AB et al. Contemporary Diagnosis and Management of Preterm Premature Rupture of Membranes. Rev. Obstet. Gynecol. 2008;1(1):11–22.
- Cousins LM et al. AmniSure Placental Alpha Microglobulin-1 Rapid Immunoassay versus Standard Diagnostic Methods for Detection of Rupture of Membranes. Am J Perinatol. 2005;(22):317-320.
- Neil PRL, Wallace EM. Is AmniSure® useful in the management of women with prelabour rupture of the membranes? Australian and New Zealand Journal of Obstetrics and Gynaecology 2010.
- Abdelazim IA, Makhlouf HH. Placental alpha microglobulin-1 (AmniSure test) versus insulin-like growth factor binding protein-1 (Actim PROM test) for detection of premature rupture of fetal membranes. J. Obstet. Gynaecol. 2013;39,6:1129–1136
- Albayrak M et al. Comparison of the diagnostic efficacy of the two rapid bedside immunoassays and combined clinical conventional diagnosis in prelabour rupture of membranes. Eur. J. Obstet. Gynecol. and Reprod. Biol. 2011;10