Guidance Update: Diagnosis and Management of PROM (Prelabor Rupture of Membranes)

SUMMARY:  

ACOG guidance on Prelabor Rupture of Membranes (PROM) addresses current literature especially related to management of late preterm PROM (34w0d to 36w6d). Following appropriate counseling, expectant management or delivery is appropriate. The use of ‘prelabor’ is in keeping with reVITALize terminology (see ‘Related ObG Topics’ below) and is defined as the ‘spontaneous rupture of membranes that occurs before the onset of labor’.

• Diagnosis
• PROM at < 24 Weeks
• Preterm PROM at 24w0d-33w6d
• Late Preterm (34w0d to 36w6d)
• Term
• PROM-related Risks
• Additional Clinical Considerations
• PROM Following Amniocentesis
• Preterm PROM and Future Pregnancies

Diagnosis

• Most cases can be diagnosed based on history and physical examination 
• Avoid digital examination due to infection risk, unless delivery appears to be immediate  
• Speculum examination  
  • Visualization of amniotic fluid (AF) leaking through the cervix  
  • Vaginal pooling
  • Fern test of dried vaginal fluid seen under microscope
  • pH testing 
    • Normal: 3.8 to 4.5
    • AF: 7.1 to 7.3 
    • False positives: Blood or semen, alkaline antiseptics or BV  
    • False negatives: Minimal remaining AF following rupture 
• If above inconclusive  
  • Ultrasound for AFV may be helpful but not diagnostic  
  • Fetal fibronectin is sensitive with high negative predictive value but positive result is not diagnostic
  • Amniotic protein tests have high sensitivity for PROM but false-positive rates may be as high as 19–30%
  • ACOG states that “These test kits should be considered ancillary to standard methods of diagnosis”

• Conclusive test – dye instillation
  • Ultrasound guided dye with passage into the vagina and detected with tampon or pad stain  
  • Maternal urine may turn blue following instillation of indigo carmine
  • See ‘Related ObG Topics’ below for alternatives to indigo carmine  

PROM at < 24 Weeks

Clinical Considerations

• Survival with PROM ≥ 22 weeks is significantly higher (57.7%) than <22 weeks (14.4%)
  • Survival rates are likely overestimated
  • Combination of birthweight, gestational age and sex will impact morbidity/mortality
    • Individualize risks
• Maternal complications
  • Infection | Endometritis | Abruption | Retained placenta  
  • Maternal sepsis risk of 1% to 4.6%
  • ACOG states

It is critically important that patients are counseled on the higher rates of morbidity associated with expectant management, which may be greater than previously reported, to ensure they can make a fully informed decision regarding their care

• Latency  
  • 40-50% will deliver within 1 week and 70-80% will deliver within 2-5 weeks  
• Pulmonary hypoplasia 
  • Will occur in approximately 10-20% of cases  
  • Insufficient data to recommend ultrasound for determination of lung volumes or function   
• Oligohydramnios can result in Potter’s deformation sequence   
  • Low-set ears | recessed chin | prominent bilateral epicanthal folds  
  • Limb contractures 
  • Skeletal malformations   

Management 

• Counsel regarding risks and benefits of expectant management vs immediate delivery  
  • Immediate delivery should be offered as an option
  • Consider MFM and neonatology consultation   
• If patient chooses expectant management and no infection  
  • Outpatient surveillance is an option following inpatient assessment  
    • Give information to return to hospital immediately if signs or symptoms of bleeding, labor or infection (self-monitor temperature) 
    • Advise return to hospital at time of viability  
• Corticosteroids and latency antibiotics 
  • Offering antibiotics as early as 20w0d is an option
  • Corticosteroids between 22w0d and 23w6d – “May be Considered … if neonatal resuscitation is planned and after appropriate counseling”
    • 22w0d to 22w6d: Single course of corticosteroids
    • 23w0d to 23w6d: Single course of corticosteroids 
• GBS prophylaxis not recommended prior to viability  
• Tocolysis is not recommended prior to viability 
• Neuroprotection (magnesium sulfate) is not recommended prior to viability

Preterm PROM at 24w0d-33w6d

• Expectant management is recommended and will usually include hospital admission with monitoring for
  • • Infection | Hemorrhage (abruption) | Umbilical cord compression | Fetal assessment | Evidence of labor
  • If there are maternal and/or fetal contraindications to expectant management, delivery is recommended  
• Antenatal (single course) corticosteroids are recommended | Insufficient evidence regarding rescue course  
• Latency antibiotics are recommended
  • Eunice Kennedy Shriver NICHD MFMU Network trial regimen  
    • IV ampicillin [2 g every 6 hours] and erythromycin [250 mg every 6 hours] for 48 hours followed by oral amoxicillin [250 mg every 8 hours] and erythromycin base [333 mg every 8 hours] for an additional 5 days (7 days total) 
    • Azithromycin (e.g., 1 g single dose) “is a suitable alternative” to replace erythromycin if unavailable or poorly tolerated
  • Amoxicillin–clavulanic acid  
    • Not recommended due to increased risk for necrotizing enterocolitis 
  • Allergy to β-lactam antibiotics 
    • “May be reasonable to consider another agent against GBS” | Choice based on severity of allergic reaction and susceptibility profiling 
  • Unclear as to whether cerclage should be removed or retained but if retained, antibiotic therapy should not be extended beyond 7 days

Note: There are multiple regimens in use | There is no evidence to support a single optimal regimen for latency antibiotics    

• Patients with PROM before 32w0d and imminent delivery are candidates for fetal neuroprotective treatment with magnesium sulfate (if no contraindications)
• Obtain vaginal/rectal swab for GBS | Administer GBS prophylaxis as indicated
• HSV infection and Preterm PROM
  • Risk of vertical transmission is 30-50% with primary HSV and 3% with recurrent HSV   
  • Recurrent active HSV  
    • Expectant management is recommended <34w0d
    • Initiate HSV therapy 
    • Corticosteroids | Antibiotics | Magnesium sulfate per indications
    • Cesarean section is indicated if active disease or prodromal symptoms are present at time of delivery   
  • Primary HSV
    • Management less clear due to high risk of vertical transmission  
    • HSV therapy is recommended  
    • Cesarean delivery recommended if active lesions are present  
• HIV infection and Preterm PROM 
  • Optimal management is uncertain due to concern of vertical transmission with PROM 
  • Management should include a physician with expertise in the management of HIV in pregnancy and standard HIV guidelines should be followed   
  • Most recent data suggest that vertical transmission risk my not be increased if the patient is on highly active antiretroviral therapy with a low viral load and has received antepartum and intrapartum zidovudine 
  • Management should be individualized 
    • If gestational age is early, but patient is on appropriate therapy with a low viral load expectant management may be appropriate  

Late Preterm (34w0d to 36w6d)

• “Either expectant management or immediate delivery is a reasonable option”
  • Data suggests when comparing these 2 options
    • No difference in neonatal sepsis
    • Newborn: Increased respiratory distress, mechanical ventilation, ICU stay in the immediate group
    • Maternal: Increased hemorrhage and infection in expectant management group
• Administer single-course corticosteroids if
  • Not previously given
  • Delivery expected in >24 hours and ≤7 days
  • No chorioamnionitis
• Screen for GBS and administer prophylaxis as indicated
• Chorioamnionitis: Treat and plan for delivery
• ACOG states (PB 831)

Care should be individualized through shred decision making, and expectant management should not extend beyond 37 0/7 weeks of gestation

Outside the scenario of unknown GBS status, latency antibiotics are not appropriate in this setting

Term (≥37w0d)

• Induction is recommended vs expectant management | Short period of expectant management (12 to 24 hours) “may be appropriately offered”
  • If no spontaneous labor, induce labor with oxytocin 
    • Allow adequate time (12-18 hours) for latent phase to progress before performing a cesarean section for failed induction of labor  
  • Induction with prostaglandins equally as effective as oxytocin but may have higher rates of chorioamnionitis  
  • Insufficient data to recommend for or against cervical ripening with mechanical methods such as a Foley balloon 
  • Insufficient evidence to recommend antibiotic prophylaxis beyond GBS indications  
• If a patient declines delivery and requests expectant management, counsel regarding risks and benefits 
  • If fetal and maternal status are reassuring, expectant management ‘may be acceptable’   
• Screen for GBS and administer prophylaxis as indicated
• Chorioamnionitis: Treat and plan for delivery

Key Points:

PROM-Related Risks 

• Preterm birth 
  • 50% of patients will deliver within 1 week 
  • Risks associate with prematurity include RDS, sepsis, IVH and NEC  
• Infection
  • Preterm PROM and intrauterine inflammation are associated with increased risk of neurologic injury   
  • Intraamniotic infection (15-25%) 
  • Postpartum infection (15-20%) 
• Abruption (2-5%) 
• Infection and umbilical cord accidents are associated with a 1 to 2% chance for fetal demise  

Additional Clinical Considerations

• Membranes may reseal spontaneously leading to good outcomes   
• Hospital admission is recommended if the fetus is viable to monitor for signs of infection, abruption and fetal compromise   
  • Acceptable strategy includes periodic ultrasound for fetal growth and FH monitoring (precise timing not established) 
  • No clinical utility evidence for the use of serial WBC counts or other infectious markers  
• Use of tocolysis  
  • Tocolytic therapy is not recommended at 34w0d to 36w7d gestation
  • Can be considered for steroid benefit at earlier gestational age and during maternal transport
• GBS as per standard protocol 
  • GBS prophylaxis should be given based on prior culture results or intrapartum risk factors if cultures not performed or unavailable 

PROM Following Amniocentesis 

• Risk of PROM following amniocentesis is 1%   
• Outpatient, expectant management  
• Monitor regularly with ultrasound and counsel patients to watch for signs of infection, bleeding and/or miscarriage  
• Contrary to spontaneous PROM, good outcomes have been reported   
  • AF fluid reaccumulated within 1 month in 72% of patients 
  • Perinatal survival rate was 91%  

Preterm PROM and Future Pregnancies  

• Increased risk of recurrent PROM and preterm birth  
• Offer progesterone supplementation starting at 16-24 weeks 
• Consider cervical length screening  

• Consider cerclage for women with the following  
  • Current singleton pregnancy 
  • Prior spontaneous preterm birth < 34 weeks  
  • Cervical length < 25 mm prior to 24 weeks  

Learn More – Primary Sources:  

ACOG Practice Bulletin 217: Prelabor Rupture of Membranes

ACOG Practice Advisory: Increased Risk of Maternal Morbidity Associated With Previable and Periviable Preterm Prelabor Rupture of Membranes

ACOG: Use of Antenatal Corticosteroids at 22 Weeks of Gestation 

ACOG Practice Bulletin 831: Medically Indicated Late-Preterm and Early-Term Deliveries

Potter’s Sequence