Transcript Preterm Labor

Preterm Labor
International
Preterm Labor
Preterm Labor
International
Objectives
• Definition and Incidence
• Etiology
• Diagnosis
• Management
- Delaying delivery
- Promoting fetal maturity
- When to transfer
- Delivery
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Definition
• regular uterine contractions accompanied by
progressive cervical dilatation and/or
effacement at less than 37 weeks gestation
 20 to 50% of PTL diagnosis is incorrect
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Dilemma
• interventions to stop preterm labor are not
particularly effective - especially when not
instituted early
'Solution'
• diagnosis based on some degree of uterine activity
combined with a single cervical exam suggesting
early dilatation or effacement
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Diagnosis
• establish dates
• history of contractions, risk factors
• abdominal exam for uterine activity
• cervical exam - serial if reasonable
• sterile speculum exam alone should be done in PPROM
• defer digital exam if there is undiagnosed vaginal
bleeding until _______ of placenta is known
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Establishing the EDD - LMP
• Naegele's Rule can be used in conjunction with the
LMP if:
- first day of last menses is known
- period was 'normal'
- cycle is regular and between 24 and 35 days
- no recent hormonal contraception, lactation or
pregnancy (3 subsequent spontaneous periods)
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Establishing the EDD - When ultrasound is
available
• Ultrasound should be used when the LMP is unknown
or criteria are not fulfilled for its use in calculating the
EDD
• U/S dating accuracy decreases as gestational age
increases
- 7 - 12 weeks GA
 ± 5 days
- 13 - 20 weeks GA
 ± 1 week
- 21 - 30 weeks GA
 ± 2 weeks
- > 30 weeks GA
 ± 3 weeks
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Establishing the EDD
• please tell someone the EDD!
- inform woman of EDD from LMP if appropriate and
reinforce at time of dating and/or 18 week
ultrasound
- document EDD on antenatal forms
- document dates and findings of each ultrasound on
antenatal (include placental location)
• good dating is useless if no one but you knows the
EDD and you are not available
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Incidence
• preterm delivery occurs in about 7% of pregnancies
• there has been little change in this rate despite new
technologies
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Significance
• preterm birth accounts for 75% of perinatal mortality
• significant longterm neonatal/pediatric sequelae
- CNS and neurodevelopmental
- respiratory
- blindness and deafness
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Etiology
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Idiopathic
Antepartum haemorrhage
Preterm prelabor rupture of membranes
Chorioamnionitis
Multiple pregnancy / Polyhydramnios
Incompetent cervix / Uterine Anomaly
Maternal disease
Fetal anomaly
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Management of Preterm Labor
Four Objectives:
1. Early diagnosis of preterm labor
2. Identify and treat the underlying cause of
preterm labor if possible
3. Attempt to stop labor when appropriate
4. Minimize neonatal morbidity and mortality
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Management - Prolongation of Pregnancy
 less than 40% of patients in preterm labor will be
candidates for tocolysis
Goal of Tocolytic Therapy
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Delay delivery when appropriate
- gain 48 hours for corticosteroids
- transport
- optimize personnel
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Management - Tocolysis Contraindicated
• contraindication to continuing pregnancy
e.g. severe pregnancy induced
hypertension, chonoamnionitis intrauterine fetal death
• contraindication to specific tocolytic agents
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Tocolytics - No strong evidence for efficacy
• Fluid bolus - small trial (n=48), no detected effect
• Ethanol
- small trials, no benefit over placebo
- ritodrine more effective in comparative trials
- concerns re: adverse effects
• Sedation - no evidence, concern re: adverse effects
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Tocolytics - No strong evidence for efficacy
• Magnesium sulfate
- small, poor quality trials; placebo and comparative
- no benefit shown
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Tocolytics - Good evidence for efficacy
• -sympathomimetics (ritodrine)
- highly effective for delaying delivery in the short term
- no demonstrated effect on neonatal outcome
• PG synthetase inhibitors (indomethacin)
- more effective than placebo in delaying delivery
>48 hours and beyond
- no demonstrated positive effect on neonatal outcome
- small trials, concern re: adverse effects
• Calcium channel blockers (e.g. nifedipine)
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Side Effects of -mimetics
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tachycardia - maternal and/or fetal
headache and nasal congestion
hyperglycemia / hypokalemia
hypotension
pulmonary edema
- multiple gestation
- other interventions
- infection
• myocardial ischemia
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Contraindications to -mimetics
• Maternal cardiac disease - structural, ischemic, rhythm
• Significant antepartum haemorrhage
• Poorly controlled medical condition
- type I diabetes mellitus
- hyperthyroidism
• Contraindication to prolongation of pregnancy
- preeclampsia or other medical indication
- chorioamnionitis, suspected fetal compromise
- mature fetus / imminent delivery / IUFD or anomaly
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Minimizing Neonatal Adverse Outcomes
• Respiratory distress syndrome (RDS) is a major
concern with preterm delivery
• Incidence of RDS has improved due to newer therapies
• RDS plays a role in several other conditions
- intraventricular haemorrhage (IVH)
- necrotising enterocolitis (NEC)
- persistent pulmonary hypertension (PPHN)
- other respiratory conditions
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Meta-analysis of Antepartum Steroids
• 15 trials evaluating antenatal glucocorticoids for the
reduction of RDS in preterm infants (>24 weeks and
< 34 weeks)
• an incomplete course of steroids may still be beneficial
P. Crowley CCPC Review No. 02955
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Effect of Corticosteroids on Neonatal Outcomes
RDS
IVH
NEC
Perinatal Infection
Neonatal Death
0.1
P. Crowley CCPC Review No. 02955
1
10
Odds Ratio (95% Confidence Interval)
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Recommendations
Which steroid ?
• betamethasone 12 mg IM q 24h x 2 doses (or q 12h)
• dexamethasone 6 mg IV q 12h x 4 doses (or q 6h)
Beware
• steroids in the presence of infection
• steroids in combination with tocolytics in multiple
gestation or diabetes
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Recommendations
When should steroid therapy be instituted?
• lower gestation limit
22 - 24 weeks
• upper gestation limit
34 - 36 weeks
• prophylactic administration
depends on
diagnosis and risk
• repeated administration
unknown
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Recommendations
Who is a candidate for antenatal steroid therapy?
preterm labour
preterm PROM
hypertensives
diabetics
IUGR
multiple gestation
YES
YES
YES
YES
YES
YES
Considerations
cause
infection
urgency
type, sugars
urgency
pulmonary edema
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Decision to Transport
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Available level of neonatal or obstetrical care
Available transport and skilled personnel
Travel time
Risk of journey - maternal and fetal/neonatal well-being
Risk of delivery en route
- Parity, length of previous labour
- State of cervix
- Contractions
- Response to tocolytics
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Transport Plan
• Copies of antenatal forms, lab results, ultrasounds
• Communication
- with patient and family
- with receiving physician re: indication, stabilization,
optimization, mode of transport, E.T.A.
• Appropriate attendant
• IV access, indicated medications, appropriate equipment
• Assess patient immediately prior to transport
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Preterm Delivery
• caesarean not indicated on basis of prematurity
• recommendation for C/S of breech < 31 weeks not
based on good evidence
• prophylactic outlet forceps not indicated
• routine episiotomy not indicated
• personnel skilled in neonatal resuscitation present
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Conclusion
• Prompt and accurate diagnosis
• Identify and treat underlying cause if possible
• Attempt to prolong pregnancy if appropriate
• Intervene to minimize neonatal mortality and morbidity
- antenatal steroid therapy
- maternal transport
- optimize local resources if unable to transport
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Prelabor Rupture of the
Membranes (PROM)
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Objectives
• Definition
• Diagnosis
• Management - Preterm and Term
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Definition
• rupture of the membranes before the onset of labor
– preterm - < 37 weeks gestation (PPROM)
– term
-  37 weeks gestation (TPROM)
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Latent Period
• time from rupture until onset of labor
• earlier the gestation the longer the latent period
• At term - 90% go into labor within 24 hours
• At 28 - 34 weeks
– 50% go into labor within 24 hours
– 80 - 90% go into labor within 1 week
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Etiology of PROM
• idiopathic
• infection (e.g. bacterial vaginosis)
• polyhydramnios
• cervical incompetence
• uterine abnormality
• following cervical cerclage or amniocentesis
• trauma
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Diagnosis of PROM
• history
• sterile speculum exam ( avoid digital exam)
– glistening, washed out vagina
– fluid pooling in posterior fornix
– free flow from cervix
– pH testing of fluid (nitrazine paper) - non specific
– ferning
• ultrasound - PROM less likely if normal fluid volume
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Complications of PROM - Term
• fetal / neonatal infection
• maternal infection
• umbilical cord compression / prolapse
• failed induction resulting in cesarean section
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Complications of PROM - Preterm
• preterm labor and delivery
• fetal / neonatal infection
• maternal infection
• umbilical cord compression / prolapse
• failed induction resulting in cesarean section
• pulmonary hypoplasia (early, severe oligohydramnios)
• fetal deformation
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Management - General
• assess maternal and fetal well-being
• confirm diagnosis
• assess cervical status by speculum exam (sterile)
• avoid digital cervical exam
• assess for conditions requiring concurrent management
e.g.
presence of temperature or maternal or
fetal tachycardia
• assess for indications for immediate delivery
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Management - Term (> 37 weeks)
• avoid digital cervical exam
• assess for infection
• consider need for antibiotics if prolonged
PROM
• expectant or active management depending on
circumstances and patient preference
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Management - Preterm (34-37 weeks)
• avoid digital cervical exam
• consider antenatal steroids
• intrapartum antibiotic prophylaxis
• surveillance for infection - clinical (monitor maternal
temperature and pulse, fetal heart rate)
• appropriate antibiotics for chorioamnionitis if develops
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Management - Preterm (< 34weeks)
• avoid digital cervical exam
• steroids
• antepartum and intrapartum antibiotics to mother
• surveillance for infection - clinical (monitor maternal pulse and
temperature, fetal heart rate, presence of uterine irritability)
• appropriate antibiotics for chorioamnionitis if develops
• consider transfer to higher level of care center if appropriate
• expectant management (possibly outpatient)
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Antibiotic options are:
Iv Penicillin G 5 million units q 4-6h preferred
or
Iv Ampiullin 2g followed by 1 g q 4h
or
IV Clindamyin 600 ng q 8h
Women with suspected chorioamnitonitis require broader
range spectrum antibiotic coverage