ducey - preterm labor

8/3/2019 Ducey - Preterm Labor

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StatenIsland Universiaty Hospital

Diagnosis and Management of

Preterm Labor

James Ducey MDStaten Island University Hospital


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Making The Diagnosis

Labor is a retrospective diagnosisOnce vaginal delivery has occurred wecan be sure the woman was in labor

There are a variety of methods we use todiagnose labor

None of them are foolproof


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Clinical Factors Used to PredictPreterm Labor

Risk assessment is a concept firstproposed by Papiernik (Presse Med 1969)

The hope was that identification ofwomen at increased risk to give birth

early prior to the onset of labor wouldlead to interventions that would preventpreterm birth


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Risk Assessment

The frequency of a large # ofdemographic and epidemiologicalmarkers in women who did and did notgive birth were compared

Scoring systems to predict which womenwere at increased risk for preterm birth


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Economic

Poor Unemployed

Father is either

Not insured No access to care

Not well fed


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Behavioral

Poor education Not compliant with prenatal care

Substance abuse

Old or young Life stresses


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Medical

Mom was small at birth Short

Underweight or overweight?

Chronic illnesses



Obstetric

Previous preterm birth Multiple birth

Acute infections

Hypertensive disorders of pregnancy Uterine anomalies



Risk Assessment

Creasy and co-workers have published anumber of more simplified scoringsystems(ObGyn 1980,1982,Birth Defects 1983)

Prospective studies have reported

sensitivities of 40

60% Positive predictive values between 15

30%



History

Pain-abdominal,back,pelvic,vaginal,gasVaginal bleeding, staining

Pelvic pressure

Urinary frequency

Diarrhea or constipation



History

Many normal women who deliver at termhave similar symptoms

Iams etal (ObGyn 1990) reported that 1/3 ofthe women they studied that developed

preterm labor had no symptoms at all



Physical Examination

Asymptomatic effacement and dilation of thecervix frequently occurs prior to labor

It may be the first sign of labor, cervicalincompetence or normal variation especially inmultiparous women

Buekens ( Lancet 1994) in a randomized study ofover 5000 women showed no difference inoutcome when cervical exam was performed atevery visit



Uterine Activity

Frequency and duration of uterinecontractions can be monitored accuratelyin an ambulatory setting

There is an increase in uterine activity in

24 hours prior to preterm labor (Katz ObGyn1986)


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Uterine Activity

Initial studies were promising In addition to uterine activity monitoring

there was a lot of nursing contact

Much controversy ensued

May diagnose preterm labor sooner

Not clinically significant


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Biochemical Markers

Estrogen

Progesterone

Prostaglandins and their metabolites

Activan

Inhibin

Collagenase

Tissue inhibitors of metaloproteinases

Fetal Fibronectin


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Fetal Fibronectin

Component of extra cellular matrix Lockwood (NEJM 1991) found that levels

were elevated in cervicovaginalsecretions in women who delivered early

AHRQ published a review of the data


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Fetal Fibronectin

7 Days


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Fetal Fibronectin AT SIUH

81 Test in 71 women

20 have delivery data

13 Negatives 8 were term 5 preterm (all 35 36

weeks) None within 7 days

7 positives 3 were term 4 preterm (all


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Endovaginal Ultrasound

Cervix visualized in great detail Funneling of the internal cervical os

Length of the cervix

Sensitivity, specificity, positive andnegative predictive values similar to fetalfibronectin


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Correction of UterineMalformations

Women with defects in lateral fusion ofthe Mullarian ducts appear to be atincreased risk for preterm labor

Surgery is usually reserved only for

habitual abortion


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Cervical Incompetence

History of cervical trauma or surgery

Two subsequent pregnancies thatterminated spontaneously in the latesecond or early third trimester and the

loss was characterized by days of pelvicpressure followed by spontaneousrupture of the membranes and quickpainless labor


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Cerclage

Has become the standard treatment Large prospective randomized study was

carried out by RCOG 1992(BJOG 1993)

A heterogeneous group of women felt to

be at increased risk for preterm birth


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Cerclage

A very safe operation There was a significant decrease in

delivery prior to 35 weeks in women whounder went cerclage

25 operations to prevent 1 preterm birth


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Pharmacological Agents

TocolyticsGlucocorticoids

Thyrotropin-releasing hormone

Antibiotics

Others


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Tocolytics

Magnesium sulfate

Beta adrenergic agonists

Prostaglandin inhibitors

Calcium channel blockers

Oxytocin-receptor antagonistEthanol

Progesterone


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Tocolytics

All these drugs seem to delay delivery 48hours

None is superior in efficacy

Delay of 48 hours improves neonatal

outcome when corticosteroids are used inconjunction


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Magnesium Sulfate

Maternal side effects are nausea,uncomfortable sensation of heat,weakness, pulmonary edema(1%) andrespiratory arrest

Fetal side effects are hypotonia andhypocalcemia


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Beta Adrenergic Agonists

Ritodrine and Terbutaline

Maternal side effects include myocardialischemia, pulmonary edema(4%),hypotension, tachycardia, hypokalemia,

hyperglycemia and acidosisFetal effects include hypotension,tachycardia, hypoglycemia andhyperbilirubinemia


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Prostaglandin SynthetaseInhibitors

IndomethacinMaternal side effects include GI upset,rash, headache and interstitial nephritis

Fetal effects include oliguria,

oligohydramnios, premature closure ofthe ductus arteriosus and pulmonaryhypertension


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Calcium Channel Blockers

NifedipineMaternal side effects include headache,nausea,flushing,hypotension,tachycardiaand hepatotoxicity

Fetal effects are not clear


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Oxytocin Receptor Blockers

Atosiban new drug that appears to beeffective

Causes nausea, headache, chest pain,arthralgias and may inhibit lactation


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Ethanol

No longer used Caused acute intoxication in the mother

May be toxic to the fetus


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Progesterones

Has been used for many years to preventmiscarriage without proven efficacy

Keirse (BrJObGyn 1990) found that whenused routinely on initial registrationresulted in a significant decrease inpreterm labor and birth

No effect on neonatal morbidity ormortality however


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Antenatal Steroids

Crowley etal(BrJObGyn 1990

) meta-analysisof 12 controlled studies

There was a significant decrease inRDS,IVH,NEC and NND

NIH conference 1995 concluded that allwomen at risk for preterm birth between24 and 34 weeks are candidates


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Antibiotics

Several studies have looked at the use ofvarious drugs to treat subclinicalinfections and prevent neonatal sepsis

Results have been inconsistent

Has not gained acceptance


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Behavioral Changes

Bed restCoitus

Substance abuse

Obesity


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Obesity

Will kill more Americans in the next 50years than cancer, cigarette smoking andHIV combined


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Obesity

Schieve etal (Epid 1999

) women withincreased weight gain during pregnancywere at increased risk for preterm birth

Rothacker etal (ADA2000) mean weight

gain of women 20

30 years of age from1992 to 1997 increased 12.1 kg


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The Future

Tocolysis will only impact on


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The Future

Reproductive endocrinologist need tolimit the # of embryos they implant

Iatrogenic prematurity continues in someplaces despite many of our best efforts

ducey - preterm labor

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