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