Transcript 041411--PPROM-Sullivan

Scott A Sullivan MD MSCR
Associate Professor - Dept Ob/Gyn
Medical University of South Carolina
Disclosure
 I have no financial stake in any products being
discussed today
 I will not talk about non-FDA approved products
Educational Goals
 Epidemiology / Mechanism of PPROM
 Diagnosis of PPROM
 Management of PPROM
Preterm Labor and Delivery

Preterm Delivery (<37 weeks)
 >540,000 (12.3%) live births annually in US
 Single largest cause of perinatal mortality and morbidity
 ~ $36 billion annual acute care costs
Preterm Birth – US (1996-2008)
13
12.5
12
1996
11.5
1998
2000
11
2002
10.5
2004
2006
10
Year
2008
6
Preterm Birth - US
South Carolina, 2007 Average
Preterm is less than 37 completed weeks gestation.
Source: National Center for Health Statistics, final natality data. Retrieved November 22, 2010, from
www.marchofdimes.com/peristats.
Pathways to Preterm Birth
Spontaneous
Preterm Labor
40%
Premature Rupture
of the Membranes
35%
Medical
Intervention
25%
Preterm
Birth
While this suggests distinct pathways, many
of the risk factors for all 3 are similar
Goldenberg, RL. The Management of Preterm Labor. Obstet Gynecol 100 (5):1020-36, Nov 2002
)
PPROM
Functions of Membranes and Amniotic Fluid
Membranes
 Barrier to infection
 Maintenance of amniotic fluid
 Storage site for phosphoglycerolipids
Amniotic Fluid
 Allows pulmonary development
 Provides for full fetal movement and growth
 Protects fetus & cord from compression and trauma
Rotschild A, et al Neonatal outcome after prolonged preterm rupture of the membranes Am J Obstet
Gynecol 162:46-52, 1990
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Membrane Functions
 Aquaporins
 Growth factors
 Oxidation?
 Paracrine functions?
Zhu, X, et al The expression of aquaporin 8 and aquaporin 9 in fetal membranes and placenta in term
pregnancies complicated by idiopathic polyhydramnios. Early Hum Dev 2010 Oct;86(10):657-63.
Membrane Structure
 Chorion (200 µm)
cytotrophoblasts
basement membrane
 Amnion (50 µm)
five layers
spongy layer (sliding)
compact layer (2nd -4th)
macrophages
mesenchymal cells
Membrane Strength
Chua W Do we know the strength of the chorioamnion?: A critical review
and analysis Eur J Ob Gyn Reprod Bio May 2009, Pages S128-S133
Mechanics of Preterm PROM
 Bacterial production of proteases
 Host response to blood or bacteria (MMP 1,2,9)
or (TIMP1,3)
 Pre-existing weakness
 Strain from preterm uterine activity
 Direct membrane trauma (cerclage or amnio)
 Developmental “weak spot”
El Khwad M, et al Term human fetal membranes have a weak zone over-lying the lower uterine pole
and cervix before the onset of labor Biol Reprod 72:720-726, 2005
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Mechanism
 Ascending infection
 Stretch
 Necrosis
 Decidual adherence
Goldenberg, R et al Epidemiology and causes of Preterm Birth Lancet 2008; 371
75-84
15
Risk Factors for PPROM
Mercer, BM et al The preterm prediction study; prediction of PPROM through
clinical findings and ancillary testing AJOG 2000 183;738-45
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Risk Factors for PPROM
 History of PPROM/PTD
 Other risk factors:
–multifetal pregnancy
–maternal age (<17 and
>35yrs)
–African-American
–low SES
–unmarried
–previous fetal or neonatal
death
–3+ spontaneous terminations
–uterine abnormalities
–shortened cervix (< 2.5 cm)
–genetic predisposition
–low pre-pregnant weight
–obesity
–infections
–bleeding
–anemia
–major stress
–lack of social supports
–tobacco use
–illicit drug use
–alcohol abuse
–conization
Risks of PPROM
 Preterm delivery
 Chorioamnionitis (13-60%)
 Non-reassuring fetal status (8 %)
 Prolapsed cord
 Abruptio placenta (4%)
 Pulmonary hypoplasia
 Cesarean section
 IUFD (1%)
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Neonatal Sepsis - PPROM
40%
PROM
20%
Intact
0%
<20
28-30
31-33
34-36
>36
Mercer B Preterm premature rupture of the membranes Obstet Gynecol 101:178-193, 2003
19
Natural History of PPROM
 Latency increases with early EGA, AFI
 ~30-50 % deliver in 48 hours
 ~90-93 % deliver in 1 week
 10 % may deliver > 4 weeks out
 Reseal? 3-10 %
Diagnosis
 Patient history
 Diagnostic tests
 US
 Don’t forget FLM!
Nitrazine (pH)
Technique:
Amniotic fluid is alkaline and, as such, turns Nitrazine pH indicator blue
Performance Metrics:




False positive results are up to 17.4%
False negative results are 12.9%
Sensitivity 90.7%
Specificity 77.2%
Drawbacks:
Speculum exam. False-positive results with other fluids, infections
Friedman, ML Diagnosis of ruptured membranes AJOG 1969 104;544-550
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Ferning
Technique:
Arborization pattern (crystallization) of dry amniotic fluid as seen
through a microscope
Performance Metrics:




False positive results are 5-30%
False negative results are 12.9%
Sensitivity 51.4% (no labor)
Specificity 70.8% (no labor)
Drawbacks:
Speculum exam, microscope. Contamination.
Reece EA, Amniotic fluid arborization Obstet Gynecol 64:248-250, 1984
23
Pooling
Technique:
Visualization of an amniotic pool in the posterior fornix
of the vagina
Accuracy:
Subjective
Drawbacks:
Speculum exam. Subjective. Other fluids.
24
Ultrasound
Technique:
Ultrasound can detect oligohydramnios, suggesting loss of
amniotic fluid due to membrane rupture
Accuracy:
Not a reliable screening test if used
alone. Used only to help confirm
diagnosis
Drawbacks:
Time-consuming. Cost. Etiology?
25
Amnio-dye Infusion
Technique:
Instillation of dilute indigo carmine into the amniotic cavity and
confirmation of rupture of membranes by documenting leakage of dye
into the vagina (staining of tampon)
Accuracy:
“Gold Standard” for diagnosis of rupture
of membranes
Drawbacks:
Accurate, but highly invasive (requires amniocentesis). Expensive.
26
Problems with Traditional Practices
 “…fern test is neither sensitive nor specific enough for
diagnostic determination of premature rupture of
membranes. We recommend against routinely providing
fern testing alone for the detection of ruptured membranes.”
 “…pH/nitrazine test is sensitive only when used in
women for whom membrane status is known. …the test
does not appear to be sufficiently sensitive or specific
enough for diagnostic determination of premature rupture
of membranes.”
NACB. Laboratory Medicine Practice Guidelines 2007. p 142-143.
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Search for New Protein Markers of ROM
 Since 1970s, multiple proteins of amniotic fluid were
discovered
 Placental Alpha Microglobulin-1 PAMG-1
 Placental Alpha Microglobulin-2 PAMG-2
 Alpha Feta Protein (AFP)
 Prolactin (PL)
 Placental Protein 12 (PP12, later called IGFBP-1)
 Fetal Fibronectin (fFn)
Search for Protein Markers of ROM
Objectives of Search

GOAL 1: to find amniotic fluid antigen with the following
criteria:

Very high concentration in amniotic fluid

Very low concentration in the background level of cervicovaginal secretions (i.e. when fetal membranes are intact)

GOAL 2: To develop antigen-specific monoclonal antibodies
(MABs) unaffected by contaminants

GOAL 3: Develop immunoassay that will utilize MAB-antigen
specific reaction to accurately and rapidly diagnose ROM
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Fetal Fibronectin (fFN)
 fFN is found to be associated with dislocation of amniotic sac
relative to cervix and is used today for detecting premature labor.
Lockwood et al., 1994
 fFN is high in maternal blood and seminal fluid. Chorionic release of
fFN can be mistaken for PPROM even though the membranes are
intact
Erdemoglu et al 2004
 The sensitivity and specificity of fFn for the detection of PROM
are 90.5% and 61.0% respectively (PPV of 54.3% and NPV of 92.6%)
Omu et al., 1997
30
PAMG-1
 Placental Alpha Microglobulin-1 (PAMG-1) is a protein
expressed by the cells of the decidual part of placenta
 Extremely low background level measured in
cervico-vaginal secretions when the fetal
membranes are intact
 During pregnancy, PAMG-1 is secreted into the amniotic
fluid in great quantities
Source: D. Petrunin, Akush Ginekol (Mosk) 1977 Jan(1):64-5
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PAMG-1 Immunoassay
PAMG-1 Test Characteristics

Immunochromatographic assay

Monoclonal antibodies used to detect PAMG-1 protein

Works within a wide range of PAMG-1 concentrations
in vaginal secretion (from 5 ng/ml to 100 mcg/ml)
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PAMG-1 Immunoassay
Administering the PAMG-1 Test
Procedure
 Step One: Vaginal swab (2-3 inches deep).
 Step Two: Swab is dipped into the vial of solvent for one minute.
 Step Three: Test strip is placed in the vial containing the specimen
extracted from the swab by the solvent.
 Step Four: Remove the strip after 5-10 minutes and read the results.
Reading the Results
1 line in the test region means No Rupture
2 lines in the test region means There is a Rupture!
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PAMG-1 Immunoassay
PAMG-1 Performance



FDA approved use of the test by nurses and
midwives as well as physicians
Clinical multi-site prospective study conducted on
patients 15-42 weeks of gestation
Cousins et al, Am J Perinat, 2005
Primary Study results:
Sensitivity: 99%
Specificity: 100%
PPV:
100%
NPV:
99%
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Diagnostic Performance
Test
Sensitivity
Specificity
Ferning/pooling1
51-98%
70-88%
84-93%
87-97%
Nitrazine (pH)1
90-97%
16-70%
63-75%
80-93%
Vaginal fFN2,1
91-98%
61-97%
54-93%
93-100%
IGFBP-11
74-97%
74-97%
73-92%
PAMG-13
98-99%
88-100%
1Caughey,
PPV
98-100%
NPV
56-87%
91-99%
et al. 2008; 2Omu et al., 1997; 3Cousins et al., 2005
PAMG-1 Immunoassay
Avoidable Costs of ROM Diagnosis
DIRECT COSTS OF ROM DIAGNOSIS
Time/Labor Costs
Estimated Pt. Time in Hospital (hrs)
Estimated Personnel Time/Pt. (hrs) - RNs
Estimated Personnel Time/Pt. (hrs) - MDs
Avg. Personnel Cost/Pt. - RN (~$34/HR)
Avg. Personnel Cost/Pt. MD (~$147/HR)
ESTIMATED TIME AND LABOR COST/PT ($)
Material Costs
pH/Nitrazin (Speculum)
Fern (microscope wear/tear, slide) (Speculum)
Pooling (Speculum)
Ultrasound AFI, use/maintenance (US$300 Assuming 30% probability of use per pt)
Indigo Carmine Amnioinfusion (US$600-1200 range, assume .05% use probability)
PAMG-1 Assay ROM Test
Old
Methods
PAMG-1
Assay
4
3
0.5
$102.00
$73.50
1*
0.25 **
0 ***
$8.50 ****
$0.00 ****
$175.50
$8.50
Old
PAMG-1
Methods
Assay
$2.33
$0.00 1
$1.71
$0.00 2
$1.50
$0.00 3
$90.00
$0.00 4
$4.50
$0.00 4
$0.00
$49.95
TOTAL MATERIAL COSTS/PT
$100.04
$49.95
TOTAL DIRECT COSTS OF ROM DIAGNOSIS
PAMG-1 Assay DIRECT SAVINGS OVER OLD METHOD PER PATIENT
$275.54
$58.45
$217.09
PAMG-1 Immunoassay
Ideal Scenario for ROM Diagnosis
 Divide patients into 2 categories:
1.
2.
Those who a grossly ruptured and have obvious ROM
diagnosis.
Those whose suspected rupture is not of a gross nature,
requiring confirmation
 Diagnose second group of patients with one reliable method
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PPROM Management
 Clinicians must weigh the risk of prolonging gestation
against the risks of serious maternal-fetal complications
while managing PROM.
 Management of PROM can include:
 Bed rest and pelvic rest * (hospital?)
 Induction of labor – to reduce risk of infection
 Tocolytics – prophylactic tocolysis after preterm PROM has been shown to
prolong latency
 Corticosteroids – to reduce respiratory distress syndrome
 Antibiotics – to prolong pregnancy, reduce infection and morbidity
38
PPROM Initial Management
 Avoid cervical checks
2.1 +/- 4.0 days
11.3 +/- 13.4 days
 Speculum exam – cultures, FLM
 Ultrasound – position, placenta
AFI < 5 critical [5 vs 14 days]
Lewis DF, Effects of digital examination on latency period for PPROM Obstet
Gynecol 1992;80 630-34
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PPROM Management
 34-36 weeks – Deliver
Chorio – 2 % vs 16 % (p<.001)
Higher pH – 7.35 vs 7.25 (p<.009)
 < 30-31 weeks expectant management
 < 23 weeks – Counseling
Survival ~ 21 %
Naef, 1991
Amniocentesis?
 Culture positive 25-40 %
 Clinical chorio 8-9 %
 Individualize
Adapted from Romero, et al 1988
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Fetal Assessment
 Safest interval is not known – daily?
 BPP < 7 associated with neonatal sepsis and chorio
 NST - conflicting data
Vintzileos – 78 %
Lewis – 39 %
 NPV for IUFD is 2/1000
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Tocolytics
 Limited Data
Levy, Weiner – prolonged latency
How – No difference in perinatal outcome
 Steroids?
 Risks?
 CP reduction? (Neuroprotection)
Combs CA AJOG 2004
Antibiotics
 NIH-MFM Trial
 IV x 48 hours, po x 5 days
 Ampicillin, Emycin
 Increased latency, decreased sepsis
composite morbidities 53% to 44%, P 0.04)
 Duration? Other agents?
Antibiotics
Canavan, T Evidence based approach to PPROM OBG Survey
2004 59
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PPROM - Steroids
 Meta-analysis indicates benefit < 32 weeks
RDS (RR, .56; CI, 0.46–.7)
IVH (RR, .47; CI, 0.31–.7)
neonatal infection (RR, 1.05; CI, 0.66–1.68)
 NIH Consensus 1994
 32-34 weeks?
Harding JE, AJOG 2001
PPROM: When to deliver?
 Mercer (1993) - RCT @ 32-36 wks (n=93)
 Management:
Expectant vs. active
 Latency (hrs)
36
14*
 Chorio (%)
28
11*
 Suspect sepsis(%) 60
28*
 Confirmed sepsis 4.3
6.8
 Antibx tx (%)
79
35*
 Home w/mom(%)
4
30*
PPROM: When to deliver
Incidence of RDS






28 weeks
30 wks
32 weeks
34 weeks
35 weeks
36 weeks
65%
50%
40%
13%*
7%*
<1%*
* majority needed suppl O2, 1.3% ventilator
PPROM: When to deliver?
 Cochrane Review (n=690) @ 32-36 wks
 Expectant vs. active management:
 neonatal sepsis (RR 1.33, (CI) 0.72 to 2.47)
 respiratory distress (RR 0.98, 95% CI 0.74 to 1.29)
 perinatal mortality (RR 0.98, 95% CI 0.41 to 2.36)
 “Insufficient data to make a recommendation. Studies
are underpowered and flawed.”
PPROM: When to deliver?
 Leiman (2005) –retrospective (n=430):
 Latency: 3.3 + 6.8 days overall
 No improvement in either major or minor
neonatal morbidity after 34 weeks
 Both maternal and neonatal LOS longer after 34
weeks with expectant management
PPROM: When to deliver?
Lieman. Preterm PROM and Neonatal Morbidity. Obstet Gynecol 2005.
Cerclage
 Conflicting evidence
Ludmir – increased latency, death
Garite – no difference
Jenkins – Increased latency, outcome same
McElrath – no difference
 Can leave or remove
Recurrence / Prevention
 Consistent recurrence risk (8-15%)
 17-OHP (Meis MFMU Study)
 Cervical length? Surveillance?
 Need more data
53
PPROM Management Summary
 Antibiotics – Yes
 Steroids – Yes (< 32 weeks)
 Deliver by 34 weeks
 Deliver for FLM, infection, NRFS
 The rest is up to you
 … and think of a good study
Thank You