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Preterm Birth

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35% of all US health care spending goes to care for preterm infants ... What awaits the pt in the near future? A. Delivery. B. PCN. C. Tocolysis ... – PowerPoint PPT presentation

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Title: Preterm Birth


1
Preterm Birth Preterm Labor
  • Julia Timofeev
  • July 25, 2007
  • University of Virginia

2
Definition
  • Preterm Birth
  • Before 37 weeks
  • Preterm Labor
  • Contractions and cervical change before 37 weeks

3
Why do we care?
  • Incidence
  • 12 of births in US
  • 2 before 32 weeks
  • Significance
  • 2nd leading cause of infant mortality
  • 50 of deaths occurred among the 1.5 of infants
    lt1500g, and 70 of deaths occurred among the 7
    of infants lt2500g
  • 35 of all US health care spending goes to care
    for preterm infants
  • Among 26wk survivors 60 disability
  • Among 31wk survivors 30 disability

4
Where do premies come from?
  • 50 due to PTL
  • 30 due to PPROM
  • 20 from medical interventions

5
Causes for preterm birth
30-50
10-30
8-9
5-40
2-4
12
6-9
6
Pathogenesis of PTL
  • Activation of maternal or fetal HPA axis
  • Infection
  • Decidual hemorrhage
  • Pathological uterine distention

7
HPA axis activation
  • Increased release of corticotropin-releasing
    hormone (i.e. placental clock)
  • Increased release of fetal pituitary ACTH
    secretion stimulates production of placental
    estrogenic compounds that activate myometrium and
    initiate labor
  • CRH enhances PGD production by amnion, chorion
    and decidua

8
Inflammation
  • Clinical and subclinical chorioamnionitis are
    much more common in preterm deliveries
  • Response is characterized by the presence of
    activated PMNs and macrophages that induce
    proinflammatory mediators such as cytokines and
    matrix metalloproteinases

9
Infection
  • Some bacteria
  • Pseudomonas
  • Staph
  • Strep
  • Enterobacter
  • Bacteroides
  • can produce proteases, collagenases and
    elastases that can degrade fetal membranes

10
Decidual hemorrhage
  • bleeding from decidual Vaginal hemorrhage is
    associated with high risk of PTL and PPROM
  • VB in more than one trimester increases risk of
  • PPROM x 7
  • PTL x 3

11
Uterine distention
  • Multiple gestation
  • Polyhydramnios
  • Enhanced stretching of myometrium induces
    formation of gap junctions, upregulation of
    oxytocin receptors and production of
    prostaglandins

12
Whos at risk?
  • Placental pathology
  • Placenta previa
  • Abruption
  • Vaginal bleeding
  • Infection
  • STDs
  • Systemic infections
  • Pyelonephritis
  • Bacteriuria
  • Cervical factors
  • h/o cervical surgery
  • Cervical insufficiency
  • Uterine distention
  • Multiple gestation
  • Polyhydramnios
  • Uterine anomaly or fibroids

13
Risk factors for preterm birth
  • Miscellaneous
  • Previous preterm delivery
  • Smoking
  • Substance abuse
  • Fetal factors
  • Congenital anomaly
  • Growth restriction
  • Stress
  • Socioeconomic factors
  • Occupational hazards

14
How short is too short
15
Did you know
  • Rate of preterm birth in African-Americans is
    significantly higher
  • It is the leading cause of neonatal death (PTB
    and low birth weight)
  • PTB in Hispanic Americans is only slightly
    increased over Caucasian population
  • Women who change their partner between 2
    pregnancies are twice as likely to deliver
    preterm

16
Risk of PTB
  • Induced abortion
  • OR 1.89, 2.66, and 2.03 w/ 1, 2, or gt3 previous
    pregnancy terminations
  • Delayed ovulation (prolonged follicular phase)
  • OR 1.5
  • Interpregnancy interval
  • Short interval inc risk

17
More interesting factoids
  • Genotypes
  • Male infants maternal immune rxn?
  • Periodontal disease
  • ? Seeding of the placenta
  • Malaria
  • Bad treat it
  • Anemia
  • lt9.5 at 12 wks ? OR 1.68

18
To treat or not to treat
  • Yeast
  • Treat it
  • BV
  • Treat it
  • Trich
  • Treat if symptomatic

19
How do we find those at risk?
  • Prediction of PTL/delivery
  • Fetal Fibronectin
  • Cervical Length
  • CRH
  • AFP and HCG
  • Alk phos

20
Fetal Fibronectin
  • Trophoblast Glue
  • Promotes cellular adhesion at uterine-placental
    and decidual-fetal membrane interfaces
  • Before collection
  • Intact membranes?
  • CVX lt3cm?
  • GA 24-34 wks?
  • Intercourse/cvx check/bleeding last 24 hrs?
  • Collect from posterior fornix

21
FFN
  • - FFN
  • Negative predictive value of 99
  • FFN
  • Positive predictive value of 13-30
  • 99.5 of symptomatic women with
  • negative FFN are undelivered at 7 days
  • 99.2 of symptomatic women with
  • negative FFN are undelivered at 14 days

22
Can we prevent it?
  • Supplemental progesterone
  • 17OHP start 2nd tri, continue until 36 weeks if
    prior delivery before 34 wks
  • QUIT SMOKING
  • Just say NO! (especially to cocaine)
  • Cervical cerclage (for cvx insufficiency)
  • Diagnose infection
  • Asymptomatic bacteriuria, BV, GC, chlam

23
What do we do in real life?
  • Triage evaluation
  • CEFM/Toco
  • SSE - ?ROM, ?VB. Collect FFN
  • Collect GC/Chlamydia cultures
  • Collect GBS culture
  • Cervical exam
  • Check UA/Urine cx

24
Dx PTL now what?
  • While in the hospital
  • CEFM/toco
  • Yeah baby, steroids!
  • BMTZ 12mg IM Q24 x 2 doses
  • Antibiotic prophylaxis for GBS
  • PCN, Cefoxetin, Clinda, Vanc
  • Tocolysis
  • PNV/Colace/FeSO4/SCDs

25
Dx PTL now what?
  • Tocolysis inhibit myometrial contractility
  • Magnesium
  • Terbutaline
  • Indocin
  • Nifedipine
  • Contraindications to tocolysis
  • IUFD, lethal fetal anomalies, NRFHT
  • Severe IUGR, chorio, hemorrhage
  • Severe pre-e/eclampsia

26
Tocolytics
27
Corticosteroids rule!
  • Why?
  • Reduce the risk of neonatal RDS, IVH, NEC, and
    mortality by 50 (FIFTY!)
  • Benefit observed 18 hours after 1st dose, max
    benefit _at_ 48 hours
  • Give 24-34 wks (?24-32wks if PPROM)
  • How?
  • Enhance maturation of lung architecture
  • Induce lung enzymes resulting in biochemical
    maturation

28
Cervical cerclage
  • For cervical insufficiency which complicates
    0.1-2 of all pregnancies and is responsible for
    20 of late 2nd trimester losses
  • Prophylactic cerclage 12-14wks
  • Rescue cerclage when cvx changes already
    detected

29
Cerclage
30
Questions for you
  • 27yo G2P0010 _at_ 31 wks presents for her New OB
    visit in triage c/o CTX. Initial evaluation
    includes
  • A. Admonishing the pt for late PNC
  • B. FFN, GC/Chlam, UA/UCx
  • C. GBS cx
  • D. Wet prep
  • E. Cvx check
  • F. B-E
  • G. All of the above

31
One more question
  • Pts cvx is 2/75/hi and then 3/90/0 in 2 hrs, you
    notice her FH is SgtD and US reveals twins of
    course! FFN is . CTX continue despite IVF. What
    awaits the pt in the near future?
  • A. Delivery
  • B. PCN
  • C. Tocolysis
  • D. Stick in the arm for BMTZ administration
  • E. More eye rolling and SW consult
  • F. All of the above
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