Twins

TwinsTopic ConferenceLU VI Block 10Tindoc.Tugano.Urquiza.Uy.Velasco.Ventigan.Ventura.Verdolaga.VillanuevaM.VillanuevaR.Visperas.Yabut.Yambot.YapB.YapJ

1Outline Case Profile Epidemiology and Etiology of Twinning Maternal Physiology Fetal Complications Labor Management and Delivery Open Forum

EV, 33 year old G2P1(0010), single3Case profileEV, 33 year old G2P1(0010), single5EV, 33 year old G2P1(0010), single6EV, 33 year old G2P1(0010), singleObstetric HistoryGDateAOGMode of Delivery120072 mos.Spontaneous Abortion22011Present pregnancy7History of present illness8Review of systems9EV, 33 year old G2P1(0010), single10Physical examination1213BPP/Biometry/Doppler Studies14BPP/Biometry/Doppler Studies15EV, 33 year old G2P1(0010), single16Etiology & epidemiology of twinningPrevalence of spontaneous twinning1 in 80 live births (1 in 40 babies)10-20/1000 live births in US, Europe40/1000 in Africa6/1000 in Asia

18Etiology of multifetal gestationDizygotic fertilization of 2 ovaMonozygotic division of single fertilized ovum

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Etiology of multifetal gestation20Factors that influence twinningRaceHeredityMaternal Age and ParityPituitary GonadotropinAssisted Reproductive TechnologyRace6/1000 livebirths in AsiaE.g. 4.3/1000 in Japan, 11.3/1000 in India, 12.3/1000 in England, WalesHeredityMaternal history more importantMothers who themselves are twins gave birth to twins at a 1/58 live birthsMaternal Age and ParityTaller, heavier more nutritionally provided women, 25-30% inc in twinning ratePituitary GonadotropinInc dizygotic twinning rate w/in 1 mo. of stopping oral contraceptives, associated with sudden surge in gonadotropinAssisted Reproductive TechnologyResponsible for 17% of multiple births in the US

21Maternal physiologyMaternal physiologyCardiovascularMore hyperdynamic circulation than singleton pregnancyGI and Hepatic ChangesNausea and vomiting in 50%Obstetric cholestasisAcute fatty liver,RenalNo significant difference from singletonCardiovascularMore hyperdynamic circulation than singleton pregnancyCardiac output increases by 20% more in twin gestation than in singleton15% from stroke volume: due to increase in preload3.5% from heart rateGI and Hepatic ChangesPregnancy nausea and vomiting 50%Twice the risk for obstetric cholestasisTwin pregnancy independent risk factor for acute fatty liver, 9-25% of all cases seen in twin pregnanciesRenalNo significant difference from singletonIncreased GFR, leads to decreased BUN, Crea and increased urine protein

23Maternal physiologyRespiratoryNo significant differenceIncreased use of accessory musclesHematologicRBC mass increases by 25% in both single and multifetal gestations Increase in plasma volume is 10-20% greater in twin pregnancy vs singletonOther changes associated with singleton pregnancy occur in the same way

RespiratoryNo significant differenceIncrease use of accessory musclesExaggerated abdominal distentionLoss of abdominal toneHematologicRBC mass increases by 25% in both single and multifetal gestations Inc. in plasma volume is 10-20% greater in twin pregnancy vs singletonOther changes associated with singleton pregnancy occur in the same wayFall in Hct 1st-2nd trimesterGranulocytosis with increase in immature WBCsHypercoagulability due to changes in coagulation and fibrinolytic cascades

24ComplicationsAntepartum complicationspreterm laborgestational diabetespreeclampsiapretermpremature rupture of the membranesintrauterine growth restrictionintrauterine fetal demiseTTTS80% in multiple gestations vs 25% in singleton pregnancies 25MATERnal complications Preterm Delivery57% of twin gestations are pretermAverage length of pregnancy is 35 wks for twins

Gestational DMMay be increased in multifetal gestation Treated the same way in twin pregnanciesPreterm Delivery57% of twin gestations are pretermNot all spontaneousHigher risk for male-male twinsAve. length of pregnancy 35 wks for twins vs 39 wks for singletonsGestational DMMay be increased in multifetal gestation though not universally confirmedTreated the same way in twin pregnancies

26Maternal complicationsPregnancy HPN Gestational HPNPre-eclampsia

PPROMOccurs in 7-10% of twin pregnanciesTypically occurs in the presenting sacManagement same as in singleton pregnancies

Pregnancy HPN Gestational HPN - RR 2.04 (95% CI 1.60 - 2.59)Pre-eclampsia RR 2.62 (95% CI 2.03 - 3.38), w/ earlier onset, greater severityGestational HPN and preeclampsia also associated with higher preterm delivery ratesGestational HPN, =20% difference in EFW5-15% of twinsUsu. birth weight difference of 15% for twins34% chance of growth restriction in at least one twin for monochorionic twins, 23% for dichorionic twinsAssociated with 6 fold increase in risk for perinatal morbidity and mortalityCongenital anomaliesStudies suggest 2-3x increased risk in twins, with probably 10% of twins born w/ congenital anomalies

29Fetal Complications Spontaneous Pregnancy Loss Intrauterine Fetal DemiseOverall survival rate of both twins is 93.7%Chorionicity important

Spontaneous Pregnancy LossAround 14% of twin gestations spontaneously convert to singleton pregnancies before the 1st trimester Vanishing twinRemaining fetus a 3x inc risk for abortionEst. that only 1/8 individuals conceived as a twin is born a twinIntrauterine Fetal DemiseOverall survival rate of both twins is 93.7%Death of one or both fetus at 11-15 wks 5% vs 2% in singletonsSubsequent risk of miscarriage of surviving fetus 24%Chorionicity importantMonochorionic twin death of one fetus inc risk of death of the other of 25%Dichorionic twin 5-10% risk

30Fetal ComplicationsTwin-to-Twin Transfusion Syndrome (TTTS)Almost exclusively confined to monochorionic twinsDue to the presence of intertwining anastomosis: A-A, V-V, A-VClassically due to A-V anastomoses carrying unidirectional blood flow from donor to recipient twin

Twin-to-Twin Transfusion Syndrome (TTTS)Almost exclusively confined to monochorionic twins, with 10-15% of these having a severe formAround of all monochorionic twins have some features of the syndromeDue to the presence of intertwin anastomosis: A-A, V-V, A-VA-V and A-A occur in 70% of monochorionic twinsClassically due to A-V anastomoses carrying unidirectional blood flow from donor to recipient twin

31Fetal complicationsTTTSDonor twin may become anemic and growth restrictedRecipient twin may become polycythemic, w/ circulatory overload and heart failureDiagnosed by UTZ at 15-22 wks.Aggressive amniodrainage and laser photocoagulation of anastomosesAcute twin-to-twin transfusionAntepartum complication in the interval of cord clamping of 1st twin and delivery of the 2nd twin2nd twin left alone with 2 placentas, where its blood may be pumped into, leading to death

TTTSDonor twin may become anemic and growth restrictedRecipient twin may become polycythemic, w/ circulatory overload and heart failureDiagnosed by UTZ at 15-22 wks.Diagnosed by presence of monochorionic twins with one oligohydramnios twin, other polyhydramnios twinMost commonly treated with aggressive amniodrainage and laser photocoagulation of anastomosesSurvival rate of at least one twin with laser therapy higher (66%) vs amniodrainage (57%)Acute twin-to-twin transfusionAntepartum complication in the interval of cord clamping of 1st twin and delivery of the 2nd twin2nd twin left alone with 2 placentas, where its blood may be pumped into - death

32DIAGnosis Suggested byAccelerated fundal growthMultiple fetal partsAuscultation of 2 FHTs Sonography the sine qua non of diagnosis

Suggested byAccelerated fundal growthMultiple fetal partsAuscultation of 2 FHTsSonography the sine qua non of diagnosisChorionicityFetal viability/diagnosis of intrauterine deathNuchal translucency thicknessChromosomal abnormalitiesEarly TTTS diagnosisFetal structural abnormalitiesIUGR, discordant growthFetal circulationPlacental localization, fetal position

33DiagnosisChorionicityEasier to determine at early gestationWhat to look forSeparate placentasIntertwin membraneExtraembryonic coelimic spaceYolk sacsFetal sexesLambda/twin peak sign

ChorionicityImportant highest rate of death in twins occurs before 24 wks, most often due to TTTSChorionicity easier to determine at early gestationWhat to look forSeparate placentas diagnostic but usu. difficultIntertwin membrane from 2 amnions, 2 chorions, >2mm in dichorionic twinsExtraembryonic coelimic space 2 in dichorionicYolk sacs 2 in dichorionicFetal sexesLambda/twin peak sign diagnostic of dichorionic twins; triangular chorionic tissue from fused dichorionic placenta extending into the intertwin membrane

34Labor management & deliveryLabor management & deliveryPrevention of preterm labor and deliveryLabor and Delivery ProblemsHypotonic uterine inertiaIntrapartum bleedingThe cornerstone of antepartum care is prevention of preterm labor and deliveryMain cause of high perinatal mortality and complications in twinsLabor and Delivery ProblemsHypotonic uterine inertiaDue to overdistended uterusOxytocin just as effective as in single births, dosage, time to delivery, complications sameIntrapartum bleedingMore common in twins due to abruptio or vasa previa

36Labor management & deliveryRoute of DeliveryVaginal delivery for mature vertex-vertex twins and