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 | *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 | *Start with ultrasound to assess position of cervix and rule out placenta previa | ||
*Swabs for fetal | *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 | *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, ABCs | |||
*Fetal Heart Monitor | *Fetal Heart Monitor | ||
*U/S to assess placental position / fetal position | *U/S to assess placental position / fetal position | ||
*Digital exam to assess cervical thickness, effacement, rupture of membranes | *Digital exam to assess cervical thickness, effacement, rupture of membranes | ||
*CBC, Chem, Coags, U/A | *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 | **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 | **Fetal fibernetin result can assist, if over 50ng/ml manage labor actively | ||
*<20mm - labor very likely | |||
* | |||
**Manage actively | **Manage actively | ||
===Management by Weeks=== | |||
*24-32 weeks | |||
**Mag sulfate (neuroprotection against cerebral palsy) | |||
*<34 weeks | *<34 weeks | ||
**Betamethasone | **Hospitalization | ||
**Tocolytics | **Betamethasone 12mg IM q24hrs x2 doses | ||
**Tocolytics (see below for options/dosages) | |||
**Antibiotics for GBS prophylaxis if status unknown | **Antibiotics for GBS prophylaxis if status unknown | ||
**Other | **Other antibiotics only indicated in setting of active infection | ||
===Tocolysis=== | |||
==Tocolysis== | |||
*Indications | *Indications | ||
**Only if fetus would benefit from delay in delivery of 48 hrs | **Only if fetus would benefit from delay in delivery of 48 hrs | ||
**Gestational age 22wks - 34 wks | **Gestational age 22wks - 34 wks | ||
**Transport to facility for definitive delivery | **Transport to facility for definitive delivery | ||
**Delay in delivery of reversible condition possibly triggering labor (UTI/pyelo) | **Delay in delivery for treatment of reversible condition possibly triggering labor (UTI/pyelo) | ||
***Betamethasone requires | ***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 | ***Tocolysis rarely effective for longer than 48 hrs | ||
***Does not remove underlying cause for tocolysis | ***Does not remove underlying cause for tocolysis | ||
*Contraindications | *Contraindications | ||
**Intratuterine fetal demise / lethal anomaly | **Intratuterine fetal demise / lethal anomaly | ||
**Maternal hemorrhage or instability | **Maternal hemorrhage or instability | ||
**Intraamniotic | **Intraamniotic infection | ||
**Severe preeclampsia or eclampsia | **Severe preeclampsia or eclampsia | ||
**Nonreassuring fetal status | **Nonreassuring fetal status | ||
**Contraindications to the drugs | **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"