Premature rupture of membranes

Premature rupture of membranes
A fetus surrounded by the amniotic sac which is enclosed by fetal membranes. In PROM, these membranes rupture before labor starts.
Classification and external resources
Specialty obstetrics
ICD-10 O42
ICD-9-CM 658.1
DiseasesDB 10600
eMedicine med/3246
MeSH D005322

Premature rupture of membranes (PROM), or pre-labor rupture of membranes, is a condition that can occur in pregnancy. It is defined as rupture of membranes (breakage of the amniotic sac), commonly called breaking of the mother's water(s),[1] more than 1 hour before the onset of labor.[2] The sac (consisting of 2 membranes, the chorion and amnion) contains amniotic fluid, which surrounds and protects the fetus in the uterus (womb). After rupture, the amniotic fluid leaks out of the uterus through the vagina.

Women with PROM usually experience a painless gush of fluid leaking out from the vagina, but sometimes a slow steady leakage occurs instead.

When premature rupture of membranes occurs at or after 38 weeks completed gestational age (at term), there is minimal risk to the fetus and labor typically starts soon after.

If rupture occurs before 37 weeks, called preterm premature rupture of membranes (PPROM), the fetus and mother are at greater risk for complications. PPROM causes one-third of all preterm births,[3] and babies born preterm (before 37 weeks) can suffer from the complications of prematurity, including death. Open membranes provide a path for bacteria to enter the womb and puts both the mother and fetus at risk for life-threatening infection. Low levels of fluid around the fetus also increase the risk of the umbilical cord compression and can interfere with lung and body formation in early pregnancy.[3]

Women who experience premature rupture of membranes should be evaluated promptly in the hospital to determine if a rupture of membranes has indeed occurred, and to be treated appropriately to avoid infection and other complications.

Classification

Signs and symptoms

Most women will experience a painless gush of fluid that leaks out of the vagina. Sometimes women notice a steady leakage of small amounts of watery fluid rather than a distinct "gush".[4] Other symptoms include a change in color and consistency of fluid coming out of the vagina, flecks of meconium (fetal stool) in the fluid, or a decrease in the size of the uterus.[5]

Risk factors

The cause of premature rupture of membranes (PROM) is not clearly understood, but the following are risk factors that have been shown to increase the chance of it happening. In many cases, however, no risk factor is identified.[7]

Pathophysiology

10-week-old human fetus surrounded by amniotic fluid and fetal membranes

Weakened fetal membranes

Fetal membranes likely break because they become weak and fragile. This weakening is a normal process that typically happens at term as the body prepares for labor and delivery. But, this can be a problem when it occurs pre-term (before 37 weeks). The natural weakening of fetal membranes is thought to be due to one or a combination of the following. In premature rupture of membranes, these processes are activated too early:

Infection

Infection and inflammation likely explains why membranes break earlier than they are supposed to. In studies, bacteria have been found in the amniotic fluid from about one-third of cases of PROM. Often, testing of the amniotic fluid is normal, but a subclinical infection (too small to detect) or infection of maternal tissues next to the amniotic fluid, may still be contributing. In response to infection, the body creates inflammation by making chemicals (ex: cytokines) that weaken the fetal membranes and put them at risk for rupture.[7] Premature rupture of membranes is also a risk factor in the development of neonatal infection.

Genetics

Many genes play a role in inflammation and collagen production, therefore inherited genes may play a role in predisposing a person to PROM.[7]

Diagnosis

Positive fern test: amniotic fluid viewed under the microscope

To know for sure if a woman has experienced premature rupture of membranes (PROM), a health care clinician must prove that (1) the fluid leaking from the vagina is amniotic fluid, and (2) that labor has not yet started. To do this, a health care clinician will take a medical history, do a gynecological exam using a sterile speculum, and ultrasound.[5]

Extra tests

The following tests should only be used if the diagnosis is still unclear after the standard tests above.

It is unclear if different methods of assessing the fetus in a woman with PPROM affects outcomes.[9]

False positives

Like amniotic fluid, blood, semen, vaginal infections,[5] antiseptics,[7] basic urine, and cervical mucus [4] also have a basic pH and can also turn nitrazine paper blue.[5] Cervical mucus can also make a pattern similar to ferning on a microscope slide, but it is usually patchy [5] and with less branching.[4]

Differential diagnosis

Other things to keep in mind that may present similarly to premature rupture of membranes are the following:[4]

Prevention

Women who have had premature rupture of membranes (PROM) are more likely to experience it in future pregnancies.[2] There is not enough data to recommend a way to specifically prevent future PROM. However, any woman that has had a history of preterm delivery, because of PROM or not, is recommended to take progesterone supplementation to prevent preterm birth recurrence.[2][5]

Management

Summary by fetal age [2]

Fetal age

Management

Term

> 37 weeks
  • Induction of labor
  • Antibiotics if needed to prevent GBS transmission

Late Pre-term

34–36 weeks
  • Same as for term

Preterm

24–33 weeks
  • Watchful waiting (expectant management)
  • Tocolytics to prevent the beginning of labor
  • Magnesium Sulfate infusion for 24-48 hours to allow maximum efficacy of steroids for fetal lungs (tocolytic) and also confer benefit to fetal brain and gut before delivery
  • One time dose of corticosteroids (2 separate administrations, 12-24 hours apart) before 34 weeks
  • Antibiotics if needed to prevent GBS transmission

Pre-viable

< 24 weeks
  • Patient counseling about watchful waiting or induction of labor
  • NO: latency antibiotics, corticosteroids, tocolysis, or MgSO4

The management of PROM remains controversial, and depends largely on the gestational age of the fetus and other complicating factors. The risks of quick delivery (induction of labor) vs. watchful waiting in each case is carefully considered before deciding on a course of action.[2]

In all patients with PROM, the age of the fetus, its position in the uterus, and its wellbeing should be evaluated. This can be done with ultrasound, electronic fetal heart rate monitoring, and uterine activity monitoring. This will also show whether or not uterine contractions are happening which may be a sign that labor is starting. Signs and symptoms of infection should be closely monitored, and, if not already done, a group B streptococcus (GBS) culture should be collected.

At any age, if the fetal well-being appears to be compromised, or if intrauterine infection is suspected, the baby should be delivered quickly by artificially stimulating labor (induction of labor).[2][6]

PROM at term

Both expectant management (watchful waiting) and an induction of labor (artificially stimulating labor) are considered in this case. 90% of women start labor on their own within 24 hours, and therefore it is reasonable to wait for 12–24 hours as long as there is no risk of infection.[6] However, if labor does not begin soon after the rupture of membranes, an induction of labor is recommended because it reduces rates of infections, decreases the chances that the baby will require a stay in the neonatal intensive care unit (NICU), and does not increase the rate of cesarean sections.[2] If a woman strongly does not want to be induced, watchful waiting is an acceptable option as long as there is no sign of infection, the fetus is not in distress, and she is aware and accepts the risks of prolonged PROM.[2] There is not enough data to show that the use of prophylactic antibiotics (to prevent infection) is beneficial for mothers or babies at or near term. Because of the potential side effects and development of antibiotic resistance, the use of antibiotics without the presence of infection is not recommended in this case.[10]

PPROM greater than 34 weeks

When the fetus is premature (< 37 weeks), the risk of being born prematurely must be weighed against the risk of prolonged membrane rupture. As long as the fetus is 34 weeks or greater, delivery is recommended as if the baby was term (see above).[2]

PPROM less than 34 weeks

Before 34 weeks, the fetus is at a much higher risk of the complications of prematurity. Therefore, as long as the fetus is doing well, and there are no signs of infection or placental abruption, watchful waiting (expectant management) is recommended.[2] The younger the fetus, the longer it takes for labor to start on its own,[5] but most women will deliver within a week.[7] Waiting usually requires a woman to stay in the hospital so that health care providers can watch her carefully for infection, placental abruption, umbilical cord compression, or any other fetal emergency that would require quick delivery by induction of labor.[2]

Pre-viable PPROM

Before 24 weeks, a fetus is not viable meaning it cannot live outside the mother. In this case, either watchful waiting at home or an induction of labor done.[2]

Chorioamnionitis

Chorioamnionitis is a bacterial infection of the fetal membranes, which can be life-threatening to both mother and fetus. Women with PROM at any age are at high risk of infection because the membranes are open and allow bacteria to enter. Women are checked often (usually every 4 hours) for signs of infection: fever ( > 38 °C/100.5 °F), uterine pain, fast maternal heart rate (>100 beats per minute), fast fetal heart rate (>160 beats per minute), or foul smelling amniotic fluid.[7] Elevated white blood cells are not a good way to predict infection because they are normally high in labor.[5] If infection is suspected, artificial induction of labor is started at any gestational age and broad antibiotics are given. Cesarean section should not be automatically done in cases of infection, and should only be reserved for the usual fetal emergencies.[5]

Outcomes

The consequences of PROM depend on the gestational age of the fetus.[4] When PROM occurs at term (after 37 weeks), it is typically followed soon thereafter by the start of labor and delivery. About half of women will give birth within 5 hours, and 95% will give birth within 28 hours without any intervention.[2] The younger the fetus, the longer the latency period (time between membrane rupture and start of labor). Rarely, in cases of preterm PROM, amniotic fluid will stop leaking and the amniotic fluid volume will return to normal.[2] The incidence of Maternal and Neonatal complications increase as the duration of PROM increases in pregnancies with full term gestation in whom labour was induced by misoprostol. PROM of more than 24 hours was found to be adversely affecting neonatal outcome in our study.[14]

Infection (any age)

At any gestational age, an opening in the fetal membranes provides a route for bacteria to enter the womb. This can lead to chorioamnionitis (an infection of the fetal membranes and amniotic fluid) which can be life-threatening to both the mother and fetus.[4] The risk of infection increases the longer the membranes remain open and baby undelivered.[2] Women with preterm PROM will develop an intramniotic infection 15-25% of the time, and the chances of infection increase at earlier gestational ages.[2]

Pre-term birth (before 37 weeks)

PROM occurring before 37 weeks (PPROM) is one of the leading causes of preterm birth. 30-35% of all preterm births are caused by PPROM.[7] This puts the fetus at risk for the many complications associated with prematurity such as respiratory distress, brain bleeds, infection, necrotizing enterocolitis (death of the fetal bowels), brain injury, muscle dysfunction, and death.[4] Prematurity from any cause leads to 75% of perinatal mortality and about 50% of all long-term morbidity.[15] PROM is responsible for 20% of all fetal deaths between 24 and 34 weeks gestation.[7]

Fetal development (before 24 weeks)

Before 24 weeks the fetus is still developing its organs, and the amniotic fluid is important for protecting the fetus against infection, physical impact, and for preventing the umbilical cord from becoming compressed. It also allows for fetal movement and breathing that is necessary for the development of the lungs, chest, and bones.[4] Low levels of amniotic fluid due to mid-trimester or previable PPROM (before 24 weeks) can result in fetal deformity (ex: Potter-like facies), limb contractures, pulmonary hypoplasia (underdeveloped lungs),[2] infection (especially if the mother is colonized by group B streptococcus or bacterial vaginosis), prolapsed umbilical cord or compression, and placental abruption.[5]

PROM after second-trimester amniocentesis

Most cases of PROM occur spontaneously, but the risk of PROM in women undergoing a second trimester amniocentesis for prenatal diagnosis of genetic disorders is 1%. Although, no studies are known to account for all cases of PROM that stem from amniocentesis. This case, the chances of the membranes healing on their own and the amniotic fluid returning to normal levels is much higher than spontaneous PROM. Compared to spontaneous PROM, about 70% of women will have normal amniotic fluid levels within one month, and about 90% of babies will survive.[2]

Epidemiology

PROM occurs in about 10-12% of all births in the United States.[2][4][5] Of all term pregnancies (> 37 weeks) about 8% are complicated by PROM,[7] 20% of these become prolonged PROM.[5] About 30% of all preterm deliveries (before 37 weeks) are complicated by PPROM, and rupture of membranes before viability (before 24 weeks) occurs in less than 1% of all pregnancies.[2] Since there are significantly fewer preterm deliveries than term deliveries, the number of PPROM cases make up only about 5% of all cases of PROM.[5]

See also

References

  1. Water breaking, Mayo Clinic
  2. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 "Practice Bulletins No. 139". Obstetrics & Gynecology. 122 (4): 918–930. October 2013. PMID 24084566. doi:10.1097/01.AOG.0000435415.21944.8f. Retrieved 12 November 2014.
  3. 1 2 3 Mackeen, AD; Seibel-Seamon, J; Muhammad, J; Baxter, JK; Berghella, V (27 February 2014). "Tocolytics for preterm premature rupture of membranes.". The Cochrane database of systematic reviews. 2: CD007062. PMID 24578236. doi:10.1002/14651858.CD007062.pub3.
  4. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Beckmann, Charles (2010). Obstetrics and Gynecology, 6e. Baltimore, MD: Lippincott Williams & Wilkins. pp. Chapter 22: Premature Rupture of Membranes, pg 213–216. ISBN 978-0781788076.
  5. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 DeCherney, Alan (2013). Current Diagnosis & Treatment : Obstetrics & Gynecology. New York: McGraw-Hill Medical. pp. Chapter 14: Late Pregnancy Complication, section: premature rupture of membranes. ISBN 978-0071638562.
  6. 1 2 3 4 Beckmann, Charles (2014). Obstetrics and Gynecology, 7e. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins. pp. Chapter 17: Premature Rupture of Membranes, pg 169–173. ISBN 978-1451144314.
  7. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Cunningham, F (2014). Williams Obstetrics. New York: McGraw-Hill Education. pp. Chapter 23: Abnormal Labor. ISBN 978-0071798938.
  8. http://www.biosynex.com/en/
  9. Sharp, GC; Stock, SJ; Norman, JE (Oct 3, 2014). "Fetal assessment methods for improving neonatal and maternal outcomes in preterm prelabour rupture of membranes.". The Cochrane database of systematic reviews. 10: CD010209. PMID 25279580. doi:10.1002/14651858.CD010209.pub2.
  10. Wojcieszek, AM; Stock, OM; Flenady, V (29 October 2014). "Antibiotics for prelabour rupture of membranes at or near term.". The Cochrane database of systematic reviews. 10: CD001807. PMID 25352443. doi:10.1002/14651858.CD001807.pub2.
  11. Kenyon, S; Boulvain, M; Neilson, JP (2 December 2013). "Antibiotics for preterm rupture of membranes.". The Cochrane database of systematic reviews. 12: CD001058. PMID 24297389. doi:10.1002/14651858.CD001058.pub3.
  12. Hofmeyr, GJ; Eke, AC; Lawrie, TA (30 March 2014). "Amnioinfusion for third trimester preterm premature rupture of membranes.". The Cochrane database of systematic reviews. 3: CD000942. PMID 24683009. doi:10.1002/14651858.CD000942.pub3.
  13. Abou El Senoun, G; Dowswell, T; Mousa, HA (14 April 2014). "Planned home versus hospital care for preterm prelabour rupture of the membranes (PPROM) prior to 37 weeks' gestation.". The Cochrane database of systematic reviews. 4: CD008053. PMID 24729384. doi:10.1002/14651858.CD008053.pub3.
  14. Outcome of Term Pregnancies with Premature Rupture of Membranes in Whom Labour was Induced with Oral Misoprostol Authors Dr Mohini Agarwal , Dr Vaishali Pachpande ,Dr Sangeeta Ramteke,Dr Shalini Fusey http://jmscr.igmpublication.org/v4-i11/11%20jmscr.pdf
  15. Hösli, Irene (2014). "Tocolysis for preterm labor: expert opinion". Arch Gynecol Obstet. 289: 903–9. PMID 24385286. doi:10.1007/s00404-013-3137-9.
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