Preterm Labor 早 产 林建华

epidemiology Labor and delivery between 28 – weeks Labor and delivery between 28 – weeks 5%-10% 5%-10% be the leading cause of perinatal morbidity and mortality be the leading cause of perinatal morbidity and mortality Survival rates have increased and morbidity has decreased because of technologic advances Survival rates have increased and morbidity has decreased because of technologic advances

Risk Factors Previous preterm delivery Previous preterm delivery Low socioeconomic status Low socioeconomic status Maternal age 40 years Maternal age 40 years Preterm premature rupture of the membranes Preterm premature rupture of the membranes Multiple gestation Multiple gestation Maternal history of one or more spontaneous Maternal history of one or more spontaneous second-trimester abortions Maternal complications (medical or obstetric) Maternal complications (medical or obstetric) --Lack of prenatal care

Uterine causes Uterine causes Myomata (particularly submucosal or subplacental) Uterine septum Bicornuate uterus Cervical incompetence Abnormal placentation Abnormal placentation

Infectious causes Infectious causesChorioamnionitis Bacterial vaginosis Asymptomatic bacteriuria Acute pyelonephritis Cervical/vaginal colonization Fetal causes Fetal causes Intrauterine fetal death Intrauterine growth retardation Congenital anomalies

diagnosis cervical effacement and/or dilatation cervical effacement and/or dilatation increased uterine irritability before 37 weeks of gestation increased uterine irritability before 37 weeks of gestationforecast: uterine activity monitoring. uterine activity monitoring. Ultrasound Examination of Cervical length Ultrasound Examination of Cervical length Fetal Fibronectin Fetal Fibronectin

treatment Bed Rest Bed Rest Tocolysis Tocolysis Corticosteroid Therapy Corticosteroid Therapy Antibiotic 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. 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. 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. 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, 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 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. 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 Tocolytic Therapy Magnesium sulfate (Intracellular calcium antagonism) Magnesium sulfate (Intracellular calcium antagonism) Terbutaline (Bricanyl) Beta2-adrenergic receptor agonist sympathomimetic; decreases free intracellular calcium ions Terbutaline (Bricanyl) Beta2-adrenergic receptor agonist sympathomimetic; decreases free intracellular calcium ions Ritodrine (Yutopar) Same as terbutaline Ritodrine (Yutopar) Same as terbutaline Nifedipine (Procardia) Calcium channel blocker Nifedipine (Procardia) Calcium channel blocker Indomethacin (Indocin) Prostaglandin inhibitor Indomethacin (Indocin) Prostaglandin inhibitor

Potential Complications Associated With the Use of Tocolytic Agents : Magnesium sulfate Pulmonary edema Pulmonary edema Profound hypotension* Profound hypotension* Profound muscular paralysis* Profound muscular paralysis* Maternal tetany* Maternal tetany* Cardiac arrest* Cardiac arrest* Respiratory depression* Respiratory depression*

Beta-adrenergic agents Hypokalemia Hypokalemia Hyperglycemia Hyperglycemia Hypotension Hypotension Pulmonary edema Pulmonary edema Arrhythmias Arrhythmias Cardiac insufficiency Cardiac insufficiency Myocardial ischemia Myocardial ischemia Maternal death Maternal death

Indomethacin (Indocin) Renal failure Renal failure Hepatitis Hepatitis Gastrointestinal bleeding Gastrointestinal bleeding Nifedipine (Procardia) Transient hypotension Transient hypotension

Corticosteroid Therapy Corticosteroid Therapy Dexamethasone and betamethasone Dexamethasone and betamethasone for fetal maturation reduces mortality, respiratory distress syndrome and intraventricular hemorrhage in infants between 28 and 35 weeks of gestation. 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 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. 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 women who received antibiotics sustained pregnancy twice as long as those who did not receive antibiotics had a lower incidence of clinical amnionitis. 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 poor fetal outcome (death, respiratory distress, sepsis, intraventricular hemorrhage or necrotizing colitis) occurred less frequently in women receiving antibiotics