Prelabour rupture of membranesAboubakr Elnashar

Benha university hospital, EgyptAboubakr Elnashar

 DEFINITIONPROM:Rupture of the membranes with leakage of amniotic fluid in the absence of uterine activity.

Pre-term PROM (PPROM):Before 37W

Term PROM (TPROM)After 37W.

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Gest age % Latent period

26 W 50 1 w

32W 50 36 h

37 W 75 24H

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 IncidencePLROM:

>37W: 8% of term pregnancies

<37: 3% of all deliveries

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AETIOLOGYMechanical

Infective

Constitutional

 

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Term PROMUsually reflects physiological processes.1.Apoptosis (programmed cell death) refers to the natural deterioration and breakdown of cells and cellular structure over time. 2. Uterine activity: As term approaches, increase Braxton-Hicks contractions: repetitive stretching of the membranes: weakening viaa.focal thinningb.strain hardening (biomechanical phenomenon associated with materials becoming less elastic and less able to withstand stress).

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In the absence of any intervention...70% of patients will labour within 24 h85% will labour within 48 h95% will labour within 96 h

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PPROMusually has pathological origins. 1.History of PPROM in a previous pregnancy

2.Ascending infection Major causeChorioamnionitis: membrane weakeningMajority: subclinical

2. Antepartum haemorrhageparticularly when recurrent 

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3. Weak cervix :It will fail as a barrier to ascending infection:membrane prolapse: localized biomechanical weakening

4. Smoking:dose dependent. reduction in smoking: reduce risk   

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CLINICAL ASSESSMENTThe correct diagnosis is crucial {unnecessary interventions: increase maternal and fetal morbidity}.

 I. HistoryGush of fluid' followed by recurrent dampness: correctly identify over 90%of cases 

 

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 II. ExaminationSterile speculum examination Performed after rest supine for 30 m.

1. AF pooling in the posterior fornix spontaneously or after fundal pressure. Absence of any pooling is an equally important. 2. Meconium should be noted. At preterm: suggestive but not diagnostic of intra-amniotic infectionAt term: relative contraindication to expectant tt

3. Cervical length and dilatation.

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Digital examination must be avoided unless the patient is thought to be in established labour

{1. increase the incidence of chorioamnionitis, postpartum endometritis, neonatal infection.

2. decreases the length of the latent period before the onset of labour}. 

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PROMVaginal Examination

24-26 26-28 28-30 30-32 32-34 34-35

Gestational Age (Weeks)

20

15

10

5Late

ncy

Day

s

No Exam

Exam

Lewis, Obstetrics & Gynecology, 1992Aboubakr Elnashar

III. Investigations

1.Bed side tests

Repeated dry pads argue against the diagnosis Pads which change colour when in contact with fluids with a pH >5.2

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Nitrazine sticks (relying on the higher alkaline pH of AF)

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Ferning pattern (when AF is dried onto a glass slide and then

viewed under a microscope).

Both:Not reliable than basic history and examination.{Appreciable false-positive and false-negative

rates}. Aboubakr Elnashar

Commercially available rapid bedside tests ExpensiveIndication: confirm or refute the diagnosis of PROM in women with negative speculum examinations.

Depend on: Substances present in high concentrations in AFFetal fibronectinInsulin-like growth factor binding protein 1 (IGFBPl), ßhCGalpha microglobulin-l (Amnisure)   Aboubakr Elnashar

Fetal Fibronectin

fFn present in cervical secretions <22 wks, >34 wks

Used for assessment of potential PTB

Positive result (>50 ng/dl) may be indicative of PROM and represents disruption of decidua-chorionic interface

In PPROM, Sensitivity-98.2%, Specificity-26.8%.

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AmniSureCost-up to $50 eachSensitivity: 98.8%, Specificity: 95%

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2. Ultrasound: AFVAs a primary diagnostic tooluseful in women with a strong history of PROM but a negative speculum examination, particularly if their symptoms persist for 48 h or more. In TPROM: Limited value: {normal variation ranging from 250 to 1200 mL}In PPROM: Very limited value {variation is much greater in preterm gestations}

Correlate with latency in PPROM and with neonatal mortality and morbidity in mid-trimester PROM.

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MANAGEMENT Term PROM

RisksFoetal: ascending infection. Maternal: uterine infection, via either chorioamnionitis or postpartum endometritis.

Risks of induction of labour:intrapartum complicationsoperative deliverypostnatal morbidity.

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Factors linked with perinatal infection1.increasing number of vaginal examinations after membrane rupture

2.increasing interval between membrane rupture and labour onset

3.increasing duration of active labour.

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Cochrane Review

12 trials of 6814 women: active Vs expectant tt: No significant difference in the rate of CS Reduced risk of chorioamnionitis Reduced risk of endometritis No significant difference in the risk of neonatal

infection but... Fewer infants requiring intensive/special care

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Immediate induction: -less maternal and neonatal infection-shorter interval from membrane rupture to delivery -No evidence that mode of delivery is influenced.

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When oxytocin is used initially:Lower health care costsDecrease interval to delivery. use of epidural analgesia is increased [A].

When prostaglandins are used initially: infection risks marginally greaterinterval to delivery slightly increasedoxytocin required subsequently in nearly half of the women [A]. Oxytocin should be regarded as the first option for induction of labour in women with prelabour rupture of membranes (WHO, 2011).

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Use of misoprostol. Cost : lower Oral: lower the risk of infection.

Induction of labour (live fetus >24 w)Vaginal: 25 ug 4-6 hrly OROrally: 50 ug 4-hrly OR 20 μg oral solution 2-hrly

Do not use if previous CS.(Weeks & Faundes 2007; WHO, 2011)

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Immediate induction of labour using oxytocin should be recommended for women known to be colonized with group B Streptococcus [B].

{Expectant management: 3-4-fold increase in risk of neonatal infection, and even immediate induction with prostaglandins failed to lower this}.

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Preterm PROM Risks1.chorioamnionitis

WBC and CRP: poor predictive abilityused to support a clinical diagnosis.

Oligohydramnios: select a group at higher risk of infection and/or earlier deliverynot diagnostic.

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Chorioamnionitis Diagnosis. maternal pyrexia (>38°C)and at least 2 of either:maternal tachycardia> 100 bpmfetal tachycardia> 160 bpm uterine tenderness · raised CRPoffensive vaginal discharge.

When clinically suspected: delivery is almost always appropriate {antibiotic therapy is rarely curative}.

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Most common organisms:anaerobes followed by group B Streptococcus and then other streptococci.

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2. PTL:In contrast to preterm labour with intact membranes, TVS measurements of cervical length are not predictive of early delivery.

3. Abruption:risk varies inversely with gestational age 5% 50%: <24 W

4. Cord prolapse

5. Operative delivery.    Aboubakr Elnashar

Management1. SteroidsAlthough neonates born after PPROM have lower incidences of RDS when compared to preterm labour, maternal steroids still appear to reduce the risk further [A]. No significant increase in maternal sepsis

   

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2. Tocolytics relatively contraindicatedknown to be less effective.PPROM in the presence of cervical cerclage: suture removal.

   

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3. Antibiotics Erthryomycin is recommended (250 mg qds for 10 d): significant reduction (from 14.4 to 11.2%) in the composite primary outcome, a measure of neonatal mortality and major morbidity [B).

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Group B Streptococcus carriers organism: usually sensitive to erythromycin.

After completion of a 10-day course, further antibiotics should probably be withheld until labour starts.

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4. Umbilical artery Doppler, biophysical Profile:

Value:1.Not effective at early identification of the infected fetus.

2. Monitoring of fetal growth {PPROM is associated with growth restriction}

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Pre-viable PROM below 23-24 ws Risks:1.Pulmonary hypoplasiaLethal{Lung development is partly reliant on normal AFV}. cannot be reliably predicted by US.

2. chronic pulmonary morbidity3. fetal limb contractures

4. extremely preterm birth with consequent co-existent morbidity and mortalityMany parents will opt for termination of pregnancy.

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PPROM at 34-37 w gestation induction, as opposed to expectant management, may lead to

less hospitalization

less perinatal infection and

less neonatal morbidity [B). 

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 In-patient versus outpatient care48-72 h: In-patient{many women will labour or develop clinical chorioamnionitis}

After this:Outpatient may be decidedInform:potential riskstemperature twice dailyS&S of developing chorioamnionitis.

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ConclusionsTerm PROM is usually a reflection of normal physiology, whereas pathological processes, such as infection and antepartum haemorrhage, often underlie PPROM.

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Accurate diagnosis of membrane rupture is essential and can usually be achieved by simple history and speculum examination alone.

A digital vaginal examination should always be avoided after PPROM unless advanced labour is suspected.

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At term, early induction using oxytocin appears to reduce perinatal infection and shorten hospital stay without increasing operative intervention.

At term, women known to be colonized with group B Streptococcus should be encouraged to allow immediate induction of labour using oxytocin after PROM.

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After PPROM, optimal management includes maternal steroids and oral erythromycin.

Maternal steroid use in PPROM reduces the risk of respiratory distress syndrome.

Erythromycin used for 10 days after PPROM is associated with a significant reduction (from 14.4 to 11.2%) in neonatal mortality and major morbidity.

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Thank youAboubakr Elnashar