妇产科学教学课件：16 Preterm Labor

早产

PretermLaborToreviewtheDefinition,frequencyandconsequenceofpretermdeliveryHighrisksforPretermdeliveryPathogenesisofPretermdeliveryPredictionofPretermdeliveryManagementofPretermlabor

Objectives

DefinitionPretermlaborPTLisalsocalledprematuredeliveryandcanleadtoanearlybirth.PTLisdefinedas:laboranddeliverybetween28-36+6weeks;Incidence:5-15%;Birthweight:1000-2500gramsPretermbirth:<37completedweeksVeryPretermbirth:<32weeksExtremelyPretermbirth:<28weeks1、Aboutaquarterofpretermbirthsareplanned.2、Therestareknownasspontaneouspretermbirths.Death,severeneonatalmorbiditiesCommonbefore26weeksUniversalbefore24weeksWorseOutcomes:ARDS——chroniclungdiseasebrainhemorrhageThresholdforneonatalmortality:1600gThresholdforneonatalmorbidity:1900g

CauseofPretermLaborDecidualhemorrhage(eg,uterineoverdistentionfrommultiplegestationorpolyhydramnios)Cervicalincompetence(eg,trauma,conebiopsy)Uterinedistortion(eg,müllerianductabnormalities,fibroiduterus)Cervicalinflammation(eg.bacterialvaginosis(BV))Maternalinflammation/fever(eg,urinarytractinfection)HormonalchangesUteroplacentalinsufficiency(eg,hypertension,insulin-dependentdiabetes,drugabuse,smoking,alcoholconsumption)PredictionofPretermDeliveryHistory:CurrentandHistoricalRiskFactorsMechanicalUterinecontractionsuterineactivitymonitoringBiochemicalFetalfibronectinUltrasoundCervicallength<25mmFetalfibronectin(fFN)

afibronectinproteinproducedbyfetalcells;foundbetweenthefetalsacandtheuterinelining;bethoughtofasanadhesiveor"biologicalglue"thatbindsthefetalsactotheuterinelining;Fetalfibronectinvs.ClinicalassessmentofPretermLaborParameterSensitivity(percent)PPV(percent)NPV(percent)

Fetalfibronectin932999Cervicaldilatation>1cm291194Contractionfrequency8/h42994PPV:positivepredictivevalue;NPV:negativepredictivevalueIams,JD,Casal,D,McGregor,JA,etal.AmJObstetGynecol1995;173:141.Sonographicassessmentofcervicallength-Transvaginal<25mm-Reproducible-SimpleClinicalDiagnosisPretermLaborSignsandsymptomsPainfulorpainlessuterinecontractionsPelvicpressureMenstrual-likecrampsWateryvaginaldischargeLowbackpainDiagnosticcriteriaUterinecontraction4in20minsor8in60minswithcervicalchangeCervicaldilatation>1cmCervicaleffacement>80%ManagementofPretermLaborBedrest:mostcommoninterventionAntibiotics:GBSprophylaxisAcceleratefetallungmaturity:dexamethasone(Dx)5mgim12hapartx4----decreaseriskforRDS,intraventricularhemorrhage,neonataldeathTocolysis:Beta-AdrenergicreceptorAgonistsMagnesiumsulfate(MgSO4)IndomethacinNifedipineBeta-adrenergicreceptoragonists

(Ritodrine利托君，安宝)MechanismInterferesw/myosinlightchainkinaseInhibitsactinmyosininteractionEfficacy48hours.NochangeinperinataloutcomeSideEffectsTachycardia,palpitations,pulmonaryedema,hyperglycemiaContraindicationsMaternalcardiacdisease,uncontrolleddiabetesandhyperthyroidismMagnesiumSulfate

MechanismofActionCalciumantagonistEfficacyUnprovenSideEffectsDiaphoresis,flushing,pulmonaryedemaContraindicationsMyastheniagravis,renalfailureCalciumChannelBlockers

(nifedipine)MechanismofActionDirectlyblockinfluxofCa++thrucellmembraneEfficacyUnprovenSideEffectsNausea,flushing,HA,palpitationsContraindicationsCaution:LVdysfunction,CHFAtosiban(阿托西班）NonapeptideoxytocinanalogueCompetitiveantagonistofoxytocin-inducedcontractionsSideeffect:Nausea,vomiting,headache,dizziness,moneylossProstaglandinInhibitorsIndomethacinTotal24hoursdose<200mgSideeffect:Oligohydramnios(reversible)PulmonaryhypertensionAnappropriatefirst-linetocolyticforpretermlaborassociatedwithpolyhydramniosDelivery:After34weeks;Evidenceofchorioamnionitis;Noreactiontoconservativemanagement;……PuerperalinfectionsPuerperalinfections,alsoknownaspostpartuminfections,puerperalfeverorchildbedfever,isanybacterialinfectionofthefemalereproductivetractfollowingchildbirthormiscarriage.