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Preterm Labor Assessment: An Evidence Based Toolkit. Herman L. Hedriana, M.D. Sac MFM Medical Group Inc. Associate Clinical Professor in Ob/Gyn UC Davis School of Medicine Mary Campbell Bliss, RN, MS, CNS Perinatal Clinical Nurse Specialist
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Preterm Labor Assessment: An Evidence Based Toolkit Herman L. Hedriana, M.D. Sac MFM Medical Group Inc. Associate Clinical Professor in Ob/Gyn UC Davis School of Medicine Mary Campbell Bliss, RN, MS, CNS Perinatal Clinical Nurse Specialist Sutter Medical Center, Sacramento
Preterm Labor and Delivery (<37 Weeks) • Preterm Labor • 800,000 (1 in 5) pregnant women in US exhibit signs and symptoms of preterm labor • 70% of women identified as “high risk” deliver at term • Preterm Delivery • >480,000 (12.3%) preterm births in 2003 • Single largest cause of perinatal mortality and morbidity Sources: National Center of Health Statistic, final natality data Retrieved Sept 2005 from www.marchofdimes.com/peristats.
Preterm Delivery Rates in the US • 27% increase in the past 20 years • Healthy People 2010 and March of Dimes goal is to reduce the rate to 7.6% by 2010 • Leading cause of neonatal morbidity and mortality
Preterm Birth Rates in Multiples • Multiple births increased from 2.4% in 1992 to 3.3% in 2002 • At least half of all twins and >90% of higher order multiples deliver preterm • The proportion of multiple preterm births increased 40% from 11.7% in 1992 to 16.4% in 2002 Multiple Birth Ratios US, 1982-2002 Rate /1000 live births
Preterm Labor • ICD-9: 644.03 • Acute Disease • Specific acute treatment • No effective prophylactic medication • High recurrence rate • Multiple triggering factors
Previous Pregnancies & Risk of Preterm Delivery • Carr-Hill; Kristensen et al.
Diagnosis of Preterm Labor • Gestational age 20-37 weeks • Documented regular UC ≥6/hour AND • At least one of the following: • Rupture of membranes • Cervical change • Cervix 2 cm dilated or 80% effaced
National Economic Burden of Preterm Labor Hospitalization • Discharge undelivered: $360,000,000 • All admissions: $820,000,000 • No change in the preterm delivery rate • Increasing perinatal morbidity • Nicholson et al. Obstet Gynecol 2000;96:95
What Women Know Re: Prematurity March of Dimes survey of 600 pregnant women • Not viewed as public health issue • Not seen as serious problem • Seen as relatively uncommon • Not see themselves at risk for preterm birth • Worry about their own unhealthy behaviors Green, et al, Contemporary OB/GYN, 48(1), 2003.
What Women Know Re: Prematurity (con’t) • 50% felt they knew signs/symptoms of preterm labor • Amniotic fluid leaks and contractions best known • Then bleeding, cramps, backache • Most call physician if experiencing preterm labor Green, et al., Contemporary OB/GYN, 48(1), 2003
California March of Dimes Prematurity Prevention Initiative • Grant to Sutter Medical Center, Sacramento • Evidence based protocol for symptomatic women • To establish a uniform diagnosis of PTL • To guide assessment and diagnosis of PTL • To avoid unnecessary hospitalizations and treatments • To decrease use of scarce nursing/hospital resources
California Maternity Hospitals • 285 hospitals and birth centers • Provide all levels of care • Goal of the grant: • One standard assessment for symptomatic PTL patients
Preterm Labor Practice Assessment Prior to development of toolkit: • Collected PTL protocols from Northern CA hospitals • Developed grids with urban/rural and NICU/no NICU groupings • Analyzed for commonalities/differences • Identified research articles for review
Preterm Protocol Findings • Consistent in some areas • Electronic fetal monitoring • MD notification • Review of prenatal record/patient history • Wide variation in other areas • Definition of preterm labor • Use of fetal fibronectin • Sterile speculum exams/vaginal exams • Disposition choices/criteria
Preterm Labor Diagnosis Reviewed current research and relevance to the diagnosis of preterm labor: • Uterine contractions • Fetal fibronectin • Cervical length • Initial goal: Sensitivity of the test • Goal of evaluation: Specificity of the test
Labor Pain • Persistent uterine contractions accompanied by dilation and/or effacement of the cervix detected by digital examination • Gonik and Creasy AJOG 1986:154;3 • Perceived contractions painful or painless but persistent • Pelvic pressure, increased vaginal discharge, backache, menstrual-like cramps • All found in term labor • Poor sensitivity and specificity • Likelihood in 7-14 days
Uterine Contractions/PTD Risk • 306 women with hx of PTD or 2nd trimester bleeding • 11 sites – from 1994-1996 • Monitored contraction 2X/day = 39,908 hours • Assessed fFN, Bishop scores, digital exams, and cervical length • Freq. of cont. higher in PM/evening hours with increasing gestation. Iams, J.D. et al. 2002
Uterine Contractions/ PTD Risk • Significant related to PTD, BUT low sensitivity and low positive predictive value for asymptomatic women • Conclusion: Increased contractions for any individual woman is more likely to reflect advancing gestation and diurnal variation than occult preterm labor Iams, J.D. et al. Frequency of Uterine Contractions and the Risk of Spontaneous Preterm Delivery. N Eng J Med 2002, 346:250-5.
4 contractions or more Low probability of preterm birth in 7-14 days Degree of pain is irrelevant Initiating treatment results in unnecessary exposure to tocolytics Hueston BJ Obstet Gynecol 1998;92:38 Iams et al NEJM 2002;346:250 Frequency of Uterine Contractions
Digital Examination • 3 cm/80%/vtx/0/SROM/BRB • Best clinical sign • 95% PPV in 7-14 days • Hueston BJ Obstet Gynecol 1998;92:38 • Assess the structure of the external os • No clinical value if cervix is < 2cm or < 80% effaced • Iams et al Obstet Gynecol 1994;84:40
Fetal Fibronectin (fFN) • Protein related to cellular cohesiveness • High levels at membrane-decidua interface • Disruption of interface releases fFN • Protein detected via immunoassay • Positive test > 50 ng/ml
Fetal Fibronectin Amnion Chorion FetalFibronectin Decidua
4500 4000 3500 3000 2500 2000 1500 1000 500 0 10 15 20 25 30 35 40 0 5 Fetal Fibronectin vs Gestational Age Clinically Relevant Time Frame (22-35 weeks) Fetal Fibronectin (ng/mL) 50 ng/mL Cutoff Level Gestational Age (weeks) Source: Adapted from Garite TJ et al. Contemp Obstet Gynecol. 1996;41:77-93.
Clinical Value of fFN • Cervix < 3cm, <80% effaced & IBOW • Sensitivity is 90% • Excellent negative predictive value within 7-14 days • 97 - 99% (24 – 28 weeks) • 95% (>28 - <34 weeks) • Poor positive predictive value (18-20%) • Iams et al AJOG 1995;173:141, Peaceman et al AJOG 1997;177:13, Leitich et al AJOG 199;180:1169
A Negative fFN Test Based on the high negative predictivevalue (NPV) of fFN, decreased levels of intervention are possible: • Reassurance and education for patient • Ongoing prenatal surveillance • Avoidance of tocolytic agents • Less disruption of patient’s lifestyle • Continue care of immediate family • Continue work • Normal ADLs
fFN in Clinical Care Algorithms • Not for establishing diagnosis • Exclusion (NPV) is its strength • Included in algorithms to exclude the likelihood of preterm labor • Must be rapidly available • Commitment to act on the result by not starting tocolytics • 3 published studies demonstrating possible impact on cost savings
fFN in Clinical Care Algorithms • In a tertiary setting: • fewer admission for PTL, shorter hospital stay, less tocolytic exposure, no adverse neonatal outcome • $486,000 saved in charges • Joffe et al AJOG 1999:180;581 • In community hospital setting: • no benefit in > 3 cm cervical dilation; 90% reduction of transfers to tertiary facility • Giles et al AJOG 2000:182;439 • Savings do not show in cost analysis models in a large teaching facility (Bethesda) • Sullivan et al JMFM 2001:10;1
Reliability of Cervical Length • Consistent images in more than 95% of patients regardless of habitus and order of multiples • Strict adherence to criteria • Superior Positive Predictive Value (PPV) to digital exam • Cervical length of 30 mm or more have very high Negative Predictive Value
Combining Cervical Length and Fetal Fibronectin • Improves accuracy of diagnosis • Goldenberg et al AJPH 1998:88;233, Rizzo et al AJOG 1996:175;1146 • In diagnosis, combined is not superior to either one alone. • Rozenberg et al AJOG 1997:176;196 • Strength consistently with exclusion • Goldenberg et al AJPH 1998:88;233
Toolkit Definition of Preterm Labor • Persistent uterine contractions • Objective documentation of cervical change • Dilated to > 2 cm or 80% effaced • Positive biochemical marker
Preterm Labor Taskforce Consensus Decisions • Labor is consistent contractions with cervical change • Rapid fFN chosen as screening test for preterm labor in symptomatic patients • Transvaginal ultrasound for cervical length is used as an adjunct of fFN • Decision to admit, discharge, transport to be made within 4 hours
PTL Assessment Toolkit Contents • PTL Care/Disposition Protocol/Algorithm • PTL Assessment Pre-Printed Orders • PTL Home Care Instructions • PTL Patient Education • Procedures (Speculum, GBS, Ferning) • Competencies • PTL Power Point Presentations
Preterm Labor Care/Disposition Protocol • Confidence that uterine contractions alone DO NOT mean labor • Contains a logical sequence of events • Disposes of clinical concerns • Should allow for a decision within 4 hours of admission
Evaluation of Symptomatic Preterm Labor • Review of history • Fetal heart and contraction monitoring • Cervical examination - look for best clinical sign • Severity of symptoms bears very little to clinical significance • Do not initiate tocolytics unless FFN and/or cervical length is assessed
COMPONENTS OF PTLASSESSMENT ALGORITHM EFM PSYCHO-SOCIAL ASSESSMENT MEDICAL ASSESSMENT HISTORY SUPPORTIVE DATA PHYSICAL ASSESSMENT SYMPTOMATIC WOMEN 20-37 WEEKS GESTATION • UA RESULTS • RISK ASSESSMENT • FLANK PAIN • SEXUAL INTERCOURSE • DEHYDRATION FETAL ASSESSMENT MEMBRANE STATUS PRETERM LABOR ASSESSMENT PRETERM LABOR SUPPORTIVE CARE HYDRATION PO OR IV POSITIONING NOTIFY PHYSICIAN STERILE SPECULUM EXAM GROUP B STREP CULTURE FETAL FIBRONECTIN TESTS ORDERED STERILE VAGINAL EXAM LABS ULTRASOUND CERVICAL STATUS ASSESSMENT
Preterm Labor Assessment Pre-Printed Physician Order Set • Concise MD order set • Rules out specific pathology • Sterile speculum exam for fFN • EFM monitoring for fetal wellbeing
Homecare Instructions • Bedrest not effective • Minimally restrictive • Effective follow-up important • Telephone calls • Frequent office visits
Preterm Labor Patient Education • “Street-smart” patients/clients • Stay with the facts….decrease confusion • Information is readily accessible • Friendly, easy reading • Warning signs to contact provider
Capping Off the Toolkit • Sterile Speculum procedure • GBS Procedure • Nursing Competencies • Sterile speculum exam • Fern testing • PTL Assessment Reference List
Preterm Labor Assessment Toolkit • A great opportunity to : • Standardize preterm labor assessment/disposition • Maintain maternal/fetal safety • Promote patient satisfaction ANY QUESTIONS??? • Contact Mary Campbell Bliss at (916) 733-8471 or Blissm@sutterhealth.org