Preterm labor: Difference between revisions

(Created page with "==Background== ==Clinical Presentation== ==Differential Diagnosis== ==Diagnosis== ==Management== ==Disposition== ==See Also== ==External Links== ==References== <refere...")
 
 
(57 intermediate revisions by 10 users not shown)
Line 1: Line 1:
==Background==
==Background==
[[File:Bumm 123 lg - Copy.jpg|thumb|Estimated gestational age based on physical exam.]]
*Defined as labor before 37 weeks (uterine contraction and cervical change)
*Increased risks to child depending on age of fetus
**Cerebral palsy, poor lung development, cognitive delay, etc
*Can be triggered by infections, stress, hypertension, uncontrolled DM


==Clinical Presentation==
==Clinical Features==
*Similar to term labor
*Uterine contractions q 10 min (may be irregular)
*New onset of vaginal mucus, [[vaginal bleeding|blood]], pink discharge, amniotic fluid
*Low [[back pain|back ache]], vaginal pressure


==Differential Diagnosis==
==Differential Diagnosis==
{{VB DDX greater than 20}}


==Diagnosis==
==Evaluation==
*Type and Screen, CBC, Chem 10, Coags, U/A with culture, Utox (cocaine increases risk of abruption)
*Do NOT perform digital exam in patients who present with vaginal bleeding when >20 weeks pregnant due to potential for placenta previa
*Start with ultrasound to assess position of cervix and rule out placenta previa
*Swabs for nitrazine, fetal fibronectin (FFN), GBS culture should also precede digital exam
**Some lubricants can affect FFN and amniotic fluid pH strip
**Nitrazine test (5% FP rate, 1% FN rate) - pH swab turns blue, indicating alkalotic amniotic fluid (pH 6.5 - 7.5 positive test); do not touch to mucous plug in cervix<ref>Nitrazine Test. https://www.pathology.med.umich.edu/poc/onsite/pH-amniotic.html</Ref>
*Proceed with digital exam if placental previa unlikely, and digital exam is urgently needed to assist patient care, such as in fetal HR decels


==Management==
==Management==
*IV access x2, ABCs
*Fetal heart monitor
*Immediate obstetrical consult
===Cervical length===
*>30mm - Labor less likely
**Observation of 6 hours might be appropriate
*20-30mm - Increased risk for preterm labor
**Fetal fibronectin result can assist, if over 50ng/ml manage labor actively
*<20mm - labor very likely
**Manage actively
===Management by Weeks===
*24-32 weeks
**[[Magnesium sulfate]] (neuroprotection against cerebral palsy)
*<34 weeks
**Hospitalization
**[[Betamethasone]] 12mg IM q24hrs x2 doses
**Tocolytics (see below for options/dosages)
**[[Antibiotics]] for GBS prophylaxis if status unknown
**Other antibiotics only indicated in setting of active infection
*34-36 weeks
**A single course of betamethasone is recommended to those who have not received a previous course <ref> https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2017/08/antenatal-corticosteroid-therapy-for-fetal-maturation#:~:text=A%20single%20course%20of%20betamethasone,previous%20course%20of%20antenatal%20corticosteroids. </ref>
===Tocolysis===
====Indications====
*Only if fetus would benefit from delay in delivery of 48 hrs
*Gestational age 22wks - 34 wks
*Transport to facility for definitive delivery
*Delay in delivery for treatment of reversible condition possibly triggering labor (UTI/pyelo)
**Betamethasone requires approximately 48 hrs for maximal benefit for lung maturity, reducing intraventricular hemorrhage, NEC, and death
**Tocolysis rarely effective for longer than 48 hrs
**Does not remove underlying cause for tocolysis
====Contraindications====
*Intrauterine fetal demise / lethal anomaly
*Maternal [[vaginal bleeding in pregnancy (greater than 20wks)|hemorrhage]] or instability
*[[chorioamnionitis|Intraamniotic infection]]
*Severe [[preeclampsia]] or [[eclampsia]]
*Nonreassuring fetal status
*Contraindications to the drugs
====Medications====
*[[Indomethacin]] 50-100mg loading dose, 25mg q4-6 hrs for 48 hrs. (avoid in gestation >32 weeks for concern of premature narrowing or closure of the ductus arteriosus)
*[[Nifedipine]] 20mg x1, additional 20mg dose in 90min if ctx persist, followed by 20mg q3-8 hrs PRN ctx
*[[Terbutaline]] 0.25mg sq q20-30 min up to 4 doses PRN ctx


==Disposition==
==Disposition==
*Admission to OB floor for delivery, or transfer to facility to manage delivery
*If cervix >30mm, contractions have stopped, consider 6 hours of obs


==See Also==
==See Also==
*[[Vaginal Bleeding (Main)]]
*[[Pregnancy (main)]]


==External Links==
==External Links==


==References==
==References==
<references/>
<references/>
*UpToDate "Overview of preterm labor and birth"
*UpToDate "Inhibition of acute preterm labor"
[[Category:OBGYN]]

Latest revision as of 00:47, 29 October 2023

Background

Estimated gestational age based on physical exam.
  • Defined as labor before 37 weeks (uterine contraction and cervical change)
  • Increased risks to child depending on age of fetus
    • Cerebral palsy, poor lung development, cognitive delay, etc
  • Can be triggered by infections, stress, hypertension, uncontrolled DM

Clinical Features

  • Similar to term labor
  • Uterine contractions q 10 min (may be irregular)
  • New onset of vaginal mucus, blood, pink discharge, amniotic fluid
  • Low back ache, vaginal pressure

Differential Diagnosis

Vaginal Bleeding in Pregnancy (>20wks)

Evaluation

  • Type and Screen, CBC, Chem 10, Coags, U/A with culture, Utox (cocaine increases risk of abruption)
  • Do NOT perform digital exam in patients who present with vaginal bleeding when >20 weeks pregnant due to potential for placenta previa
  • Start with ultrasound to assess position of cervix and rule out placenta previa
  • Swabs for nitrazine, fetal fibronectin (FFN), GBS culture should also precede digital exam
    • Some lubricants can affect FFN and amniotic fluid pH strip
    • Nitrazine test (5% FP rate, 1% FN rate) - pH swab turns blue, indicating alkalotic amniotic fluid (pH 6.5 - 7.5 positive test); do not touch to mucous plug in cervix[1]
  • Proceed with digital exam if placental previa unlikely, and digital exam is urgently needed to assist patient care, such as in fetal HR decels

Management

  • IV access x2, ABCs
  • Fetal heart monitor
  • Immediate obstetrical consult

Cervical length

  • >30mm - Labor less likely
    • Observation of 6 hours might be appropriate
  • 20-30mm - Increased risk for preterm labor
    • Fetal fibronectin result can assist, if over 50ng/ml manage labor actively
  • <20mm - labor very likely
    • Manage actively

Management by Weeks

  • 24-32 weeks
  • <34 weeks
    • Hospitalization
    • Betamethasone 12mg IM q24hrs x2 doses
    • Tocolytics (see below for options/dosages)
    • Antibiotics for GBS prophylaxis if status unknown
    • Other antibiotics only indicated in setting of active infection
  • 34-36 weeks
    • A single course of betamethasone is recommended to those who have not received a previous course [2]

Tocolysis

Indications

  • Only if fetus would benefit from delay in delivery of 48 hrs
  • Gestational age 22wks - 34 wks
  • Transport to facility for definitive delivery
  • Delay in delivery for treatment of reversible condition possibly triggering labor (UTI/pyelo)
    • Betamethasone requires approximately 48 hrs for maximal benefit for lung maturity, reducing intraventricular hemorrhage, NEC, and death
    • Tocolysis rarely effective for longer than 48 hrs
    • Does not remove underlying cause for tocolysis

Contraindications

Medications

  • Indomethacin 50-100mg loading dose, 25mg q4-6 hrs for 48 hrs. (avoid in gestation >32 weeks for concern of premature narrowing or closure of the ductus arteriosus)
  • Nifedipine 20mg x1, additional 20mg dose in 90min if ctx persist, followed by 20mg q3-8 hrs PRN ctx
  • Terbutaline 0.25mg sq q20-30 min up to 4 doses PRN ctx

Disposition

  • Admission to OB floor for delivery, or transfer to facility to manage delivery
  • If cervix >30mm, contractions have stopped, consider 6 hours of obs

See Also

External Links

References

  1. ↑ Nitrazine Test. https://www.pathology.med.umich.edu/poc/onsite/pH-amniotic.html
  2. ↑ https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2017/08/antenatal-corticosteroid-therapy-for-fetal-maturation#:~:text=A%20single%20course%20of%20betamethasone,previous%20course%20of%20antenatal%20corticosteroids.
  • UpToDate "Overview of preterm labor and birth"
  • UpToDate "Inhibition of acute preterm labor"
Retrieved from "https://www.wikem.org/w/index.php?title=Preterm_labor&oldid=371825"