妇产科学课件：Preterm labor

1、Preterm labor Definition Prematrue labor or deliveryLabor spontaneously occurring after 28 weeks but before 37 weeks gestation, fetal weight 2500gmain cause of neonatal morbidity in developed countriesEtiology Obstetric complicationsPlacenta abnormalities: Placenta previa, placenta abruption, Diabet

2、es, hypertensionPolyhydramnios, oligohydramniosPremature rupture of membraneMultiple gestationPrevious laceration of cervix or uterusShort internal between pregnancies (30mm, high negative predictive value, in the second and third trimesters Fetal fibronectinProtein of the choriodecidual matrixAbsen

3、t from cervicovaginal secretions after 20 weeks, until delivery beginsIn posterior fornix, negative swab, predictive of absence of a Preterm labor within following 7 daysTreatment Goals Inhibit or reduce uterine contractionsOptimize fetal status before deliveryShort-term goal Continue the pregnancy

4、for 48h after steriod administrationLong-term goal Continue the pregnancy beyond 34 -37weeksEvaluationGestational ageFetal weightPresenting partFetal monitoring12Treatment Preterm labor should be allowed in following casesMaternal diseases and disorders: Severe hypertensive disease, Pulmonary or car

5、diac disease, Maternal severe hemorrhageFetal diseases and disorders: Fetal death or distress, Intrauterine infection, Polyhydramnios accompanying with malformationOthers : Cervical dilatation of more than 4cm, Ruptured membrane: controversyTreatment Bed restThe most common interventions used for pr

6、evention and/or treatment of threatened preterm laborLeft lyingTreatment Inhibit uterine contractionHydration/sedationPretherapy before tocolysisWhen gravida without medical complicationsPethidine: 50100mg imTreatment Tocolysis The fetus is healthyGestational week is 2034 ( up to 37 week if no inten

7、sive neonatal care)Cervical dilatation is 4cm and effacement is 97%15002000g 90%10001500g 6580%8001350g 66%Mortality and morbidity rates are higher in smaller fetusesPrevention Regular and good antenatal careTreat pregnancy complicationPrevent premature rupture of membrane and subclinical infectionS

8、uture cervical incompetence (cerclage) between 14th 18th weekThank you !Treatment-mimetic adrenergic agents: 2 the most common usedIncrease cAMP in celldecrease free calcium, relax uterus and uterine vesselsSide effects: hypotension, maternal and fetal tachycardia, decreased serum K+, increased gluc

9、ose and pulmonary edemaContraindicationsCardiac disease, hyperthyroidism, uncontrolled hypertension and diabetes, asthmaTreatmentRitodrine:Initial dose is 50100 g/min increased by 50g/min, until labor stop, maintain for 12 hours. Max dose 350 g/min10 mg po 30 min prior to stopping iv, followed by 10

10、 mg every 2 hr or 20mg every 4 hr for 24 hr. If stable reduce to 1020mg every 4 to 6 hr. Max dose 120mg /dayTreatmentTerbutaline initial dose is 10 g/min iv increase by 5 g/min every 10 min, max dose is 25 g/min5mg po every 68 hr or 2.5mg every 4 hr Sulbutamolloading dose is 4.8mg po, followed 2.44.8mg every 8 hoursTreatmentMagnesium sulfateBest alternative of beta-mimetic drugsCompete with cal