Preterm Labor

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Preterm Labor

• Ayesha Shaikh
• PGY3
• Emory Family Medicine
• 06.17.10

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Case!

• One innocent Emory Family Medicine resident!
• Age unknown!
• G4P1A2 at 25.5 wks GA, presented in didactics on
  one pleasant morning of Feb 2010.
• Later seen by perinatology for Antiphospholipid
  syndrome.Asymptomatic otherwise!
• Transvaginal ultrasound shows cervical funneling
  and shortening to 0.5 cm. Immediately put on bed
  rest, Steroids administered and 3 days later
  admitted in hospital for
• PRETERM LABOR!

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Defination

• Preterm Birth
• Before 37 weeks
• Preterm Labor
• Contractions and cervical change before 37 weeks

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Why care?

• Incidence
• 12 of births in US
• 2 before 32 weeks
• Significance
• 2nd leading cause of infant mortality
• Infant mortality rates are function of
  gestational age at birth and increase
  significantly before 32 weeks gestation
• 35 of all US health care spending goes to care
  for preterm infants
• Among 26wk survivors 60 disability
• Among 31wk survivors 30 disability

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Where do premies come from?

• 50 due to PTL
• 25 due to PPROM
• 25 iatrogenic

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Causes of preterm birth
30-50
8-9
10-30
2-4
5-40
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6-9
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Todays Focus

• Spontaneous preterm labor
• with intact membranes

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Risk Factors

• Maternal
• Race,
• Interpregnancy interval,
• Prepregnancy BMI 19
• Pregnancy Hx
• Previous preterm delivery
• Medical disorders

• Pregnancy characterisitcs
• Infections
• Cocaine/heroine
• Cone biopsy/LEEP
• Abd surgery
• Multiple gestation
• Periodontal disease
• Shortened Cervix
• Tobacco
• Uterine anomalies
• Vaginal bleed

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Ethnic rates!

• Rate of preterm birth in African-Americans is
  significantly higher- 18.4
• PTB in Hispanic Americans is only slightly
  increased (12.1) over Caucasian population
  (11.7)

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Cervical Length

• Shortened Cervix is less than 3 cm or a funneling
  configuration at internal os in 2nd trimester
  transvaginal Ultrasound
• Cervical effacement in normal pregnancy at 32 wks
• A short cervix confers a higher risk of preterm
  delivery

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Cervical funneling
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Prevention of Preterm Delivery

• Smoking cessation
• Bacteriuria?
• Periodontal disease?
• Bacterial vaginosis?
• Antenatal Progesterone?

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Bacterial vaginosis and PTL

• Screening and treatment for prevention
  contraversial.
• For history of preterm birth, screening reduces
  PPROM and LBW but not PTL.
• USPSTF recommends AGAINST screening low risk
  patients.

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BV diagnosis

• Amsel Criteria?
• KOH amine odor, clue cells on saline prep,
• PH gt 4.5, and a thin homogenous vaginal
  discharge
• (need 3/4)
• CDC Rx
• Clindamycin 300mg PO BID x 7 days
• Flagyl 500 mg BID x 7 days
• Prefer Clindamycin!

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Antenatal progesterone

• Prevents formation of cellular gap junctions and
  maintains uterine quiescence.
• 250 mg IM/week from 16-20 weeks through 36 weeks
  gestation.
• Lower risk of NE, IVH, and less need for
  supplemental oxygen
• Twin pregnancies?
• ACOG, limit use to women with a previous
  spontaneous birth at less than 37 weeks gestation.

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Assessment of PTL

• What is the gestational age?
• Are the membranes ruptured?
• Is the patient in labor?
• Is there an infection?
• What is the likelihood that the patient will
  deliver prematurely?

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Rupture of membranes?

• Sterile speculum exam and FFN
• Nitrazine test accuracy of 97
• Ferning has accuracy of 84-100
• False positive
• Nitrazine test in presence of bleed, semen,
  urine, vaginal infections and Ferning in presence
  of cervical mucus.
• Oligohydroamnios is suggestive of but not
  diagnostic of ROM. Confirm with Amnioinfusion of
  indigo carmine.

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Assessment

• What is the gestational age?
• Are the membranes ruptured?
• Is the patient in labor?
• Is there an infection?
• What is the likelihood that the patient will
  deliver prematurely?

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Infection

• Evaluate UA for Bacteruria and Pyelpnephritis
• Rectovaginal culture for GBS
• Screen for GC and Chlamydia if not done earlier
• Evaluation for BV and trichomoniasis and
• Treatment does not effect pregnancy duration

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Assessment

• What is the gestational age?
• Are the membranes ruptured?
• Is the patient in labor?
• Is there an infection?
• What is the likelihood that the patient will
  deliver prematurely?

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Determine likelihood of true labor

• Labor regular uterine contractions at least
  6/hr,
• With descent of fetal presenting part,
• Progressive dilation at least 3 cm
• Effacement of cervix to 80
• Rupture of membranes or vaginal bleed
• However patients present with incomplete picture

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Determine likelihood of true labor

• FFN Superior to cervical dil and contraction in
  symptomatic women
• NPV 99 and PPV 13-30
• NOT if done vag exam, intercourse,
  endovaginal ultrasound within past 24 hours.
• Confounders vag bleed, ROM, Abnormal vag
  flora, vaginal lubricants
• Cervical Ultrasound determine cervical length
• Most deliveries within 7 days if length less
  than 1 cm.
• FFNCervical US is more accurate tha either test
  done alone

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Management

• Steroids!
• BMTZ 12mg IM Q24 x 2 doses
• DexMTZ 6 mg IM Q24 x 4 doses
• Antibiotic prophylaxis for GBS
• PCN, Cefoxetin, Clinda, Vanc
• Tocolysis
• PNV/Colace/FeSO4/SCDs

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Management

• GBS prophylaxis for culture GBS, GBS
  bacteruria and prior newborn infected with GBS
• Dose
• PenG 5 mu bolus IV -gt2.5 muQ4 hr till
  delivery
• Ampicillin 2 gm bolus -gtI gm Q4 till
  delivery
• Penicillin allergy
• Clindamycin 900mg IV Q 8 hrs till delivery
• Or
• Erythromycin 500 mg Q 6 hrs till delivery
• Vanc 1gm Q12 hrs till delivery

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Tocolysis

• Lacks robust outcome-based research support
• Buy time to administer steroids.
• General contraindication fetal distress,
  Chorioamnionitis, and maternal instability

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Tocolytics

• Indomethacin
• CI maternal hepatic or renal impairment,
  oligohydroamnios, PUD
• SE constriction of ductus arteriosis-
• DO NOT use after 32 wks GA
• IVH, NE, hyperbili.

• Magnesium Sulfate
• CI Mysthenia Gravis
• SE flushing, lethargy HA, diplopia, dry mouth,
  pulmonary edema, newborn hypotonia, respiratory
  depression

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Tocolytics

• Terbutaline
• CI heart disease, poorly controlled DM,
  thyrotoxicosis,
• SE cardiac arrythmias, pulmonary edema, MI,
  hypotension, tachycardia, Hyperglycemia,
  hypokalemia, tremor, nervousness, palpitations,
  nausea, vomiting
• Fetal tachycardia, hypoglycemia, hyperbili, IVH

• Nifedipine
• CI maternal hypotension
• SE flushing, HA, diziness, nausea, transient
  hypotension
• No fetal SE noted

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Tocolytics

• Nifedipine
• CI maternal hypotension
• SE flushing, HA, diziness, nausea, transient
  hypotension
• No fetal SE noted

• Terbutaline
• CI heart disease, poorly controlled DM,
  thyrotoxicosis,
• SE cardiac arrythmias, pulmonary edema, MI,
  hypotension, tachycardia, Hyperglycemia,
  hypokalemia, tremor, nervousness, palpitations,
  nausea, vomiting
• Fetal tachycardia, hypoglycemia, hyperbili, IVH

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Tocolytic Doses

• Indomethacin
• Loading 50 mg rectal or 100 mg oral, maintenance
  25-50 mg oral Q4 hrs for 48 hrs
• MagSO4 4-6 g bolusIV over 20 min, then 1-2 gm
  /hr( max 3 g/hr)

• Nifedipine 30 gm loading dose orally, then 10
  -20 mg every four to six hours
• Terbutaline 0.25 mg SC every 20 to 30 minutesfor
  four hou to six doses.
• 5 mg PO every 4 hours.
• TERBUTLAINE PUMP!

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Delivery of the Preterm Infant

• Level III NICU for care of preterm infant.
• Fetal injury due to Acidosis, anoxia.
• Perform continuous electronic fetal monitoring.
• The immaturity of fetus and Tolcolytic adverse
  effects complicate fetal surveillance.
• Does prophylactic episiotomy, forceps
  delivery, or c-section improve neonatal outcome?
• Common retained placenta. Send cord acid-base
  studies.

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Coming back to the Innocent EFM Resident!
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• Subsequent Transvaginal US
• 0.5 cm short cervix ---gt finger tip inone week!
• It is snowfall week of Feb 2010.
• Dose 1 Betamethasone IM at OB office
• Dose 2 Betamethasone IM
• self administered at home.
• OUCH!

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OUCH! OUCH! OUCH!

• Terbutaline pump catheter in thighs, change Q 3
  days
• Lovenox injection on pregnant belly, Q daily
• Weekly Progesterone injection in the buttock
• Two rounds of Betamethasone injection in Deltoids

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Also!

• Failed Nifedipine due to hypotension
• Unable to tolerate Terbutaline PO
• Terbutalin pump and Q 4 hrs tachycardia, missing
  beats and nervousness lasting 90 min each episode.

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Ended up!

• Epidural induced hypotension
• Nubaine induced Vomitings
• C section related intra-op bleed needing blood
  transfusion TWICE.
• AND

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Yes ! It is lunch hour!I know!I am done!