Preterm labor: Difference between revisions
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==Background== | ==Background== | ||
*Defined as labor before 37 weeks (uterine | *Defined as labor before 37 weeks (uterine contraction and cervical change) | ||
*Increased risks to child depending on age of fetus | *Increased risks to child depending on age of fetus | ||
**Cerebral palsy, poor lung development, cognitive delay, etc | **Cerebral palsy, poor lung development, cognitive delay, etc | ||
*Can be triggered by | *Can be triggered by infections, stress, hypertension, uncontrolled DM | ||
==Clinical Features== | |||
*Similar to term labor | *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== | ==Differential Diagnosis== | ||
{{VB DDX greater than 20}} | |||
* | ==Evaluation== | ||
* | *Do NOT perform digital exam in patients who present with vaginal bleeding when >20 weeks pregnant | ||
*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== | ||
*IV access, ABCs | |||
*Fetal Heart Monitor | |||
*U/S to assess placental position / fetal position | |||
*Digital exam to assess cervical thickness, effacement, rupture of membranes | |||
*Type and Screen, CBC, Chem 10, Coags, U/A with culture, Utox (cocaine increases risk of abruption) | |||
==Management== | ===Cervical length=== | ||
*>30mm - Labor less likely | |||
**Observation of 6 hours might be appropriate | |||
*20-30mm - Increased risk for preterm labor | |||
**Fetal fibernetin result can assist, if over 50ng/ml manage labor actively | |||
*<20mm - labor very likely | |||
**Manage actively | |||
===Management by Weeks=== | |||
*24-32 weeks | |||
**Mag 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 | |||
===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 | |||
**Intratuterine fetal demise / lethal anomaly | |||
**Maternal hemorrhage or instability | |||
**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 | |||
**[[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]] |
Revision as of 07:53, 7 July 2017
Background
- 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)
- Emergent delivery
- Placental abruption
- Placenta previa
- Vasa previa
- Uterine rupture
- Preterm labor
- Vaginal trauma
- Placenta accreta
- Intrauterine fetal demise
Evaluation
- Do NOT perform digital exam in patients who present with vaginal bleeding when >20 weeks pregnant
- 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, ABCs
- Fetal Heart Monitor
- U/S to assess placental position / fetal position
- Digital exam to assess cervical thickness, effacement, rupture of membranes
- Type and Screen, CBC, Chem 10, Coags, U/A with culture, Utox (cocaine increases risk of abruption)
Cervical length
- >30mm - Labor less likely
- Observation of 6 hours might be appropriate
- 20-30mm - Increased risk for preterm labor
- Fetal fibernetin result can assist, if over 50ng/ml manage labor actively
- <20mm - labor very likely
- Manage actively
Management by Weeks
- 24-32 weeks
- Mag 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
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
- Intratuterine fetal demise / lethal anomaly
- Maternal hemorrhage or instability
- 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
- 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
- ↑ Nitrazine Test. https://www.pathology.med.umich.edu/poc/onsite/pH-amniotic.html
- UpToDate "Overview of preterm labor and birth"
- UpToDate "Inhibition of acute preterm labor"