Diagnosing Premature Rupture of Membranes

Births that follow spontaneous preterm labor (PTL) and preterm premature rupture of membranes (pPROM) are together designated as spontaneous preterm births. Spontaneous preterm births account for ~70% of all premature deliveries, where the remaining 30% are indicated as a result of maternal or fetal infection.1 Of those births classified as spontaneous preterm births, 64% are the result of preterm labor (PTL) and 36% are the result of preterm premature rupture of membranes (pPROM).

PPROM is defined as spontaneous rupture of the membranes at less than 37 weeks of gestation at least one hour before the onset of contractions. Common symptoms include complaints of leakage in the absence of active labor. Traditional diagnostics methods include nitrazine/pH, ferning, and ultrasound. Indigo carmine intra-amniotic injection may be indicated if status remains questionable after all other methods are performed.2

The exact mechanism(s) of PPROM is largely unknown, but is believed to include: bacterial production of proteases and phospholipases, host response to blood or bacteria resulting in leukocyte activation and cytokine release, weakness from over distention, strain from preterm uterine activity, direct membrane trauma (cerclage or amniocentesis), or a developmental weak spot.3

Over the past century, countless approaches have been proposed for the diagnosis of PROM.4 When symptoms are pronounced, the diagnosis of PROM (i.e. gross rupture of membranes with obvious fluid leakage) is easy to make. However, in 40-47% of patients presenting with suspicion of ROM, obvious leakage from the cervix cannot be visualized and the diagnosis becomes difficult to confirm or rule out.5,6

Standard diagnostic methods, including nitrazine, ferning, pooling and ultrasound, alone or in combination with one another, have proven inaccurate in such cases. In the absence of an accurate test to diagnose or rule out ROM, the patient is at a greater risk for not receiving the necessary interventions, including appropriate use of steroids. Failure to implement salutary measures can have both significant medical and financial implications for the payer, the mother and baby, as well as for the hospital and the obstetrician. Conversely, a false positive diagnosis can lead to unnecessary hospitalizations and induction of labor.

Significant financial impact results from the use of the PAMG-1 test primarily due to: (i) reductions in costs associated with false diagnoses using traditional methods and (ii) reductions in current spending on ROM diagnosis in non-obvious cases using traditional methods.

  • Goldenberg RL, Culhane JF, Iams JD, Romero R. Lancet. Epidemiology and causes of preterm birth. 2008 Jan 5;371(9606):75-84.
  • ACOG Practice Bulletin (Mercer). Premature Rupture of Membranes No. 80, 2007
  • Caughey AB, Robinson JN, Norwitz ER. Contemporary diagnosis and management of preterm premature rupture of membranes. Rev Obstet Gynecol 2008;1:11–22.
  • El-Messidi A, Cameron A. Diagnosis of premature rupture of membranes: inspiration from the past and insights for the future. J Obstet Gynaecol Can 2010;32:561–569.
  • Nisell H, Hagskog K, Westgren M. Assessment of fetal fibronectin in cervical secretion in cases of equivocal rupture of the membranes at term. Acta Obstet Gynecol Scand. 1996 Feb;75(2):132-4.
  • 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 Dec;50(6):534-8.


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