Preterm Labor
早 产
林建华
epidemiology
? Labor and delivery between 28 – 36+6 weeks
? 5%-10%
? be the leading cause of perinatal morbidity
and mortality
? Survival rates have increased and morbidity
has decreased because of technologic
advances
Risk Factors
? Previous preterm delivery
? Low socioeconomic status
? ? Maternal age <18 years or >40 years
? Preterm premature rupture of the membranes
? Multiple gestation
? Maternal history of one or more spontaneous
second-trimester abortions
? Maternal complications (medical or obstetric)
--Lack of prenatal care
? Uterine causes
Myomata (particularly submucosal or
subplacental)
Uterine septum
Bicornuate uterus
Cervical incompetence
? Abnormal placentation
? Infectious causes
Chorioamnionitis
Bacterial vaginosis
Asymptomatic bacteriuria
Acute pyelonephritis
Cervical/vaginal colonization
? Fetal causes
Intrauterine fetal death
Intrauterine growth retardation
Congenital anomalies
diagnosis
? cervical effacement and/or dilatation
? increased uterine irritability before 37 weeks
of gestation
forecast,
? uterine activity monitoring,
? Ultrasound Examination of Cervical length
? Fetal Fibronectin
treatment
? Bed Rest
? Tocolysis
? Corticosteroid Therapy
? Antibiotic Therapy
? Although bed rest is often prescribed for
women at high risk for preterm labor and
delivery,there are no conclusive studies
documenting its benefit,
? A recent meta-analysis found no benefit to
bed rest in the prevention of preterm labor or
delivery,
? Tocolytic therapy may offer some short-term
benefit in the management of preterm labor,
? A delay in delivery can be used to administer
corticosteroids to enhance pulmonary
maturity and reduce the severity of fetal
respiratory distress syndrome,
? also be used to facilitate transfer of the
patient to a tertiary care center
? No study has convincingly demonstrated an
improvement in survival,long-term perinatal
morbidity or mortality,or neonatal outcome
with the use of tocolytic therapy alone,
? Tocolytic Therapy
? Magnesium sulfate (Intracellular calcium
antagonism)
? Terbutaline (Bricanyl) Beta2-adrenergic
receptor agonist sympathomimetic;
decreases free intracellular calcium ions
? Ritodrine (Yutopar) Same as terbutaline
? Nifedipine (Procardia) Calcium channel
blocker
? Indomethacin (Indocin) Prostaglandin
inhibitor
Potential Complications Associated With the
Use of Tocolytic Agents,
Magnesium sulfate
? Pulmonary edema
? Profound hypotension*
? Profound muscular paralysis*
? Maternal tetany*
? Cardiac arrest*
? Respiratory depression*
Beta-adrenergic agents
? Hypokalemia
? Hyperglycemia
? Hypotension
? Pulmonary edema
? Arrhythmias
? Cardiac insufficiency
? Myocardial ischemia
? Maternal death
Indomethacin (Indocin)
? Renal failure
? Hepatitis
? Gastrointestinal bleeding
Nifedipine (Procardia)
? Transient hypotension
? Corticosteroid Therapy
? Dexamethasone and betamethasone
? for fetal maturation reduces mortality,
respiratory distress syndrome and
intraventricular hemorrhage in infants
between 28 and 35 weeks of gestation,
? benefits start at 24 hours and last up to
seven days after treatment
? The potential benefits or risks of repeated
administration of corticosteroids after seven
days are unknown,
? women who received antibiotics sustained
pregnancy twice as long as those who did not
receive antibiotics
? had a lower incidence of clinical amnionitis,
? poor fetal outcome (death,respiratory distress,
sepsis,intraventricular hemorrhage or
necrotizing colitis) occurred less frequently in
women receiving antibiotics