PRETERM LABOR
    Janet Gould, DO
            Case Presentation
   HPI: You are called to triage to see a 26 yo AAF
    G2 P0101 c/o pelvic pressure & a lower
    backache. States she is having menstrual-like
    cramping. Denies any vaginal bleeding or LOF.
    She is at 28 wks gest by dates & early U/S.
   OBHx: 1st child delivered by C/S @ 29 wks after
    tocolysis w/ MgSO4 & terbutaline had failed &
    fetus was found to be breech
   PMHx: Chlamydia infxn x 3; last episode in 1st
    trimester of current pregnancy
You are concerned this patient may be in
preterm labor. What are her
for preterm labor?

Click on “answer” to see if you are correct.
The patient presented in the case has the
following                   for preterm labor:

       1. African American race
       2. Prior h/o preterm labor
       3. H/o chlamydial infxn during current

*Click the “info button” to view other risk factors for PTL.
Maternal Factors                 Infection
  -   Low socioeconomic status   - Chorioamnionitis
  -   Nonwhite race              - BV
  -   Maternal age <18 or >40    - STDs
  -   Low prepregnancy wt
  -   Smoking/Substance abuse

Maternal Hx                      Uterine Factors
  - Previous h/o PT delivery     - Multiple gest; polyhydraminos
  - H/o 2nd trimester Ab         - Uterine anomalies
You are in the triage room obtaining the pt’s
complete hx & verifying her dates. The triage
nurse appears to be in quite a hurry. She asks if
you will need anything, as she quickly puts on the
maternal & fetal monitors. You tell her:

     Yes, you will need to do a speculum exam.
     Yes, you just need to do a cervical exam.
     No, you just want to wait & see what’s on the
              : perform a speculum exam

Why do a speculum exam?
    To check for fetal fibronectin.
    To check vaginal cultures.
    To do a GBS culture.
    To check for ROM.
    All of the above.
   There is one step you must do first that
    cannot be done after a digital exam.

   And you always want to be active in your
    management of a PTL pt. Waiting is not
    the appropriate answer.

You perform a speculum exam in order to
obtain vaginal cultures, a GBS cx and fetal
fibronectin. A sterile speculum exam is also
necessary in order to check for ROM.
You are partially correct. Actually, you want
to check all of these tests.

So, you perform the sterile speculum exam
& collect vaginal cx, GBS & FF. She clearly
has not had ROM. Thus, you do a digital
exam & find: 2cm/50%/-2.

The nurse leaves the room. You then finish
the PE.

Click on the file folder to view the results of the exam.

.                                            Patient File
                     Physical Exam
   VS: T:98.7 BP:110/76 P:78 R:12
   PE:
•   Gen: anxious; AAO x 3; NAD
•   HEENT: wnl
•   Neck: (-) thyromegaly; (-) LAD
•   Lungs: CTA b/l; (-)w/r/r
•   Heart: Grade 2/6 SEM @ LLSB
•   Abd: gravid; non-tender; (-)rebound/guarding
•   Ext: (-) c/c/e
•   Neuro: CNII-XII intact; (-)focal deficits; 2+DTRs
•   VE:
          cervix: 2/50%/-2; no abnormal vag d/c
          fundus: 30cm
          presentation: breech
   You have completed the maternal exam.

   You now wish to assess fetal well-being.
    How would you do so?

                       : External Monitoring & U/S

   External monitoring is used to determine FHR
    pattern & ctx pattern

   U/S is used to determine gest age, presentation,
    placental location & fetal anomalies.

Click on “results” to view the findings on
external monitor & U/S.
   External Monitoring
    FHR:160’s (+)accels (-)decels (+)LTV
    Toco: mild ctxs q 8-10min

   U/S (performed by OB resident on-call):
    gest age: 28 weeks size (+/- 2 wks)
    presentation: breech
    AFI: 15

 26 yo G2P1 @ 28 wks gest c/o pelvic
  pressure & ctxs
 Has previous h/o PTL

 Cervical exam: 2cm/50%/-2

 Toco w/ mild ctx q 8-10 min.

 FHT w/ a reassuring pattern

 Fetal fibronectin RETURNS    RESULT
Fetal fibronectin result:

             What is Fetal Fibronectin?

  - Protein found in the fetal membrane, decidua & amniotic
  fluid. It functions as adhesive between embryo & uterus.
  - As the gestational sac implants, FF normally appears in
  cervicovaginal fluid, but the presence FF is rare after 24th
  - After 24th wk, +FF may indicate detachment of fetal
    membrane from decidua
  - Important to memorize about FF test: excellent negative
  predictive value, i.e. if FF is negative, <1% of women will
  deliver in next week.

You believe you have gathered all of the necessary
  information to diagnose PTL. To be certain, you search
  the internet for information on diagnosing PTL.

                         Click Here
       Preterm Labor: Diagnosis
   Identify si/sx of PTL √
   Pt between 20 and 36 wks √
   Uterine ctxs @ 4 per 20 min or 8 per 60 min √
   Ctxs accompanied by:
     - PROM
     - Dilation > 2 cm √
     - Effacement > 50% √
     - Or cervical change detected by serial exams

Based upon the info. You have gathered on
your patient, you are still unsure if you can
dx. the pt with PTL. What other test can
you do to help you in your PTL evaluation?

      Transvaginal Ultrasound
 Cervical length may be a useful predictor
  of PTL, w/ shorter cervix predicting higher
  risk of PT delivery
 Given many variations of digital exams, it
  is thought transvaginal U/S allows an
  objective approach to the cervical exam
 The OB resident helps you to perform the
  transvaginal U/S - - the           : 2.5 cm

       Preterm Labor Evaluation:
    Utility of Fetal Fibronectin & U/S
   If dx of PTL is uncertain, obtaining fetal
    fibronectin & transvaginal U/S is a
    reasonable strategy
   If FF (-) & cervical length > 3cm, pt can
    be sent home b/c likelihood of delivering
    in next week <1%

Now, you are very concerned about the
Possibility of PTL, especially due to her risk
factors, freq ctxs, FF & cervical length.
What management strategies should you be
thinking about?

Click on the “info button” to learn more about PTL management
    Preterm Labor: Management
   Therapeutic Goals:
     1) inhibit/reduce strength & freq of ctxs,
        thus delaying time to delivery
     2) optimize fetal status before PT delivery
   Consider                           , including:
     1)   Tocolytic therapy
     2)   Corticosteroids
     3)   Antibiotics
     4)   Transfer to tertiary care center

   After reviewing the management strategies,
    you consider starting tocolytics.
   Will tocolytics prevent preterm labor? If
    not, what are the benefits of using

Click on the “info button” to find out more
about tocolytic therapy.
       PTL Treatment: Tocolytics
   Tocolytics stop ctxs temporarily, but do not prevent
    preterm birth
   Used alone, they convey little or no benefit in neonatal

   They are effective in delaying delivery for 24 - 48°, which
    is long enough for administration of steroids & transfer to
    tertiary care center
   Can have adverse health effects on women
   Contraindications :
    - nonreassuring FHT             - eclampsia
    - fetal demise                  - chorioamnionitis
    - fetal maturity                - maternal instability
   Which tocolytic will you
    use? What dose will you
   You go to your palm pilot
    for some more info.
    regarding tocolytics.

Click on the “palm pilot” to review
* MgSO4                                 * Nifedipine
-   Ca2+ antagonist                     - Ca2+ channel blocker
-   4g load IV, then 1-3g/hr            - 20mg po, then 10-20mg q 6-8°
-   SE: resp & cardiac arrest           - SE: maternal hypotension
-   Monitor DTRs & Mg levels            - Monitor BP

* Terbutaline                           * Indocin
- ß2 activator                          - Prostaglandin inhibitor
- 0.25- 0.5mg SC q 30min                - 50mg load, then 25mg q6 °
- SE : ischemia, arrhythmias &          - SE: maternal GI upset; oligo;
      pulm edema                              ductal constriction
- Monitor cardiac rhythm, fluid/lytes   - Not used after 32 wks

 You decide to use             for
 You order 0.25mg SQ x 1 q 30min.

   Your patient has been in
    triage for 2 hours. She
    has received 2 doses of
    Terbutaline, but
    continues to contract
    every 5-10min. You
    re-examine her cervix &
    find: 3cm/50%/-2

   Yikes !! You now confirm the dx. of PTL:
        - regular ctxs
        - cervical change

   You decide to transfer care of this preterm labor
    patient to OB , but they’re all in C/S!! What else
    can you do in the meantime to improve the
    newborn’s chance of survival?

    PTL Treatment: Corticosteroids
   Steroids are the only tx that improves fetal
    survival when given 24-34 wks gestation.
   They are typically not used >34 wks, b/c
    perinatal outcomes are generally good.
   Studies have shown a decrease in intravent.
    hemorrhage, RDS & mortality w/ steroid tx.
   Optimal benefits begin 24hrs after tx & last
    for 7 days
   Based upon this info, your patient at
    28 wks gest would benefit from steroid

   Typically, what steroids are used in the
    management of PTL? What are the
    appropriate doses?

      Corticosteroid Therapy

     Treatment regimens for PTL include :

   Betamethasone 12mg IM q 24° x 2 days
   Dexamethasone 6mg IM q 12° x 2 days

   You have diagnosed your patient @ 28 wks gest
    age with PTL.
   You started tocolytic therapy with terbutaline in
    order to delay delivery.
   This allows time to administer steroids to
    enhance fetal lung maturity.
   Now, what about antibiotics? Do we need them?

      PTL Treatment: Antibiotics
   Infections play an etiologic role in PTL
   Pts in PTL are at high risk for neonatal GBS
    sepsis & should receive prophylactic antibx.
   Initiate at dx of PTL & continue until delivery
   Tx will prevent perinatal transmission
   This approach will not prevent PTL

 Since your pt is <37 wks gest age, you
  want to start antibiotics for GBS prophylaxis.
 What antibxs are used for GBS prophylaxis?
  What are the appropriate doses?

               GBS Prophylaxis
   PCN G
    5 million U IV load, then 2.5 million U
    q 4 hrs until delivery
   Amp
    2g IV load, then 1 g IV q 4 hrs until delivery

   If PCN allergic,
    Cleocin 900 mg IV q 8hrs until delivery, or
    E-mycin 500mg IV q 6 hrs until delivery

   You’ve got the tocolytics, steroids
    & antibx on board.

   You’re at MUSC which has a NICU,
    thus there is no need to transfer care.

   If labor continues to progress, how will you
    deliver the baby, vaginally or via C/S?

   Birth at a center with a NICU is one of the
     best predictors of neonatal survival
   In PTL, likely to have fetuses born breech
         - less likely to have traumatic & asphyxial injuries
           when delivered via C/S
   In PT vertex infants, C/S performed for same
    indications as in term infants
         - no evidence that delivery by C/S improves
   Recall that the U/S showed the baby in a breech
    presentation. Thus, a C/S will be performed to deliver
    the baby.

Click on summary to review PTL strategies.        Summary

   Preterm delivery accounts for substantial component of
    all neonatal M&M.
   Effective interventions to decrease spontaneous preterm
    delivery have not been discovered.
   Successful management includes:
    - preventing neonatal dz
    - use of corticosteroids for fetal maturation
    - when appropriate, GBS prophylaxis
    - reducing trauma & asphyxia during delivery
    - transferring to site that can perform expert
      resuscitation & provide intensive care
                                                 Click to view
   Beckmann, Charles R. et al. Obstetrics and Gynecology.
    4th edition. 2002; 304-311.
   Goldenberg, Robert L. The management of preterm
    labor. The American College of Obstetricians and
    Gynecologists. November 2002. Vol. 100, Number 5,
    Part 1; 1020-1037.
   Newton, Edward R. Preterm Labor. E-medicine. Sept.
    15, 2005.
   Von Der Pool, Beverly A. Preterm Labor: Diagnosis and
    Treatment. Amer Family Physician. May 15, 1998.
   Weismiller, David G. Preterm Labor. Amer Family
    Physician. Feb. 1, 1999.

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