Fetal Membrane Rupture

Rupture of membranes (ROM) is one of the most common complications of pregnancy. It is estimated to be a factor in approximately one third of all preterm births.1 Ruptured fetal membranes can occur both before and at term. In either case, early intervention is essential to reducing the risk of complications.

Types of Placental Rupture and Epidemiology

Rupture of fetal membranes from 37 weeks’ gestation onwards is known as PROM (premature rupture of membranes). It is associated with a number of complications including fetal distress, umbilical cord prolapse and compression, and increased risk of perinatal infection. Between 8-10% of all pregnancies will experience spontaneous rupture of membranes prior to the onset of labor.2

Preterm premature rupture of membranes (pPROM) is any rupture of the fetal membrane before 37 weeks. pPROM occurs in 3% of pregnancies. It is a major contributor to mortality, having been associated with 18-20% of all perinatal deaths in the US.2

Management of ROM During Pregnancy

Evidence suggests that latency periods are shorter the closer to term ROM occurs.3 As a result, it is generally recommended that when fetal rupture happens at 34 weeks or later, pregnancy should be induced. This greatly reduces the risk of complications and infections.

Testing for ROM During Pregnancy

Since the 1940s, a number of tests have been employed for diagnosing ROM during pregnancy. A visual inspection may confirm the presence of amniotic pooling in the posterior fornix. However, the process is invasive, accuracy is subjective, and as many as 47%4 of ROM during pregnancy cases present no observable pooling of amniotic fluid at the cervical os.

Other diagnostic methods include nitrazine testing and ferning, both of which offer low specificity and commonly produce false positives and false negatives. For the nitrozine test a speculum exam is required to collect the sample. False-positive results may be caused by cervicitis, vaginitis (bacterial vaginosis or Trichomonas), alkaline urine, blood, semen, or antiseptics. In the case of ferning, Speculum exam is also required to collect the sample, it requires microscope and false positives may result from contamination of slide with fingerprints, semen and/or cervical mucus. False negatives may be caused by dry swabs, contamination with blood and discharge. The additional drawback for ferning is the lack of certified personnel available on the L&D floor to read the slides or the lab’s requirement to have the slides sent down to the lab.

Intra-amniotic instillation of indigo carmine has been considered a gold standard of testing for fetal membrane rupture, however it's expensive and highly invasive. As a result it is no longer used in North America, Europe or Asia.

Biomarker Testing for Fetal Membrane Rupture

Biomarker testing for ROM during pregnancy has been shown to offer the best combination of specificity and sensitivity. AmniSure® is an established biomarker test that identifies the presence of the PAMG-1 protein, present in the amniotic fluid of pregnant women. Compared to other testing methods, AmniSure® is non-invasive, easy to use and ~99% accurate, making it an excellent choice for any clinic, hospital or midwifery practice.

  • ACOG Committee on Practice Bulletins-Obstetrics. ACOG Practice Bulletin No. 80: premature rupture of membranes. Clinical management guidelines for obstetrician-gynecologists. Obstet. Gynecol. 2007;109:1007-1019
  • Caughey, AB et al. Contemporary Diagnosis and Management of Preterm Premature Rupture of Membranes. Rev. Obstet. Gynecol. 2008;1(1):11–22.
  • Hannah ME et al. Induction of labor compared with expectant management for prelabor rupture of the membranes at term. N. Engl. J. Med. 1996;334:1005–10.
  • 47%: 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.

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