Rupture of membranes

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Rupture of membranes (ROM) or amniorrhexis is a term used during pregnancy to describe a rupture of the amniotic sac.[1] Normally, it occurs spontaneously at full term either during or at the beginning of labor. Rupture of the membranes is known colloquially as "breaking the water" or as one's "water breaking." A premature rupture of membranes (PROM) is a rupture of the amnion that occurs prior to the onset of labor.

Sometimes, a child is born with no rupture of the amniotic sac (no rupture of membranes).


When the amniotic sac ruptures, production of prostaglandins increases and the cushioning between the fetus and uterus is decreased, both of which processes increase the frequency and intensity of contractions.[2]

On occasion, with the rupture of membranes, particularly if the head is not engaged, the umbilical cord may prolapse. A cord prolapse is an obstetrical emergency, as the descending head may block fetal-placental circulation.

Once the membranes are ruptured, bacteria may ascend and could lead to amnionitis and fetal infection.


  • SROM: spontaneous rupture of membranes. This term describes the normal, spontaneous rupture of the membranes at full term. The rupture is usually at the bottom of the uterus, over the cervix, causing a gush of fluid. This gush may be quite small (such as 50ml), or it can be significantly large (200-300ml) depending upon amount of fluid in the amniotic sac, and to what extent the fetal head is plugging the hole and retaining fluid in the sac.[3]
  • PROM : premature rupture of membranes. This term describes a rupture of the membranes that occurs before the onset of labor.
    • PPROM : preterm, premature rupture of membranes. This term describes a rupture of the membranes that occurs before 37 weeks gestation.


Detection of rupture of membranes mainly include:[4]

  • Pooling test: visualization of amniotic fluid pooling in the vagina
  • Nitrazine paper test
  • Fern test


  1. ^ "amniorrhexis" at Dorland's Medical Dictionary
  2. ^ American Pregnancy Association > Inducing Labor Last Updated: 01/2007
  3. ^ > Birth > Spontaneous Rupture of Membranes By Paula Skelton, midwife
  4. ^ Bennett, S.; Cullen, J.; Sherer, D.; Woods Jr, J. (2008). "The Ferning and Nitrazine Tests of Amniotic Fluid Between 12 and 41 Weeks Gestation". American Journal of Perinatology 10 (2): 101–104. doi:10.1055/s-2007-994637. PMID 8476469. 

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