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Multifetal Pregnancy. Radha Venkatakrishnan Clinical Lecturer Warwick Medical School. Incidence : Monozygotic twins - 4/1000 births Dizygotic twins – 2/3rds, race, age, assisted conception Triplets – 1 in 7000 to 10,000 births Quadruplets – 1 in 600,000 births - PowerPoint PPT Presentation
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Multifetal PregnancyRadha VenkatakrishnanClinical LecturerWarwick Medical School
Incidence :Monozygotic twins - 4/1000 birthsDizygotic twins 2/3rds, race, age, assisted conceptionTriplets 1 in 7000 to 10,000 birthsQuadruplets 1 in 600,000 births Almost every maternal and obstetric problem occurs more frequently in multiple Pregnancy Perinatal mortality rate in twins is 5 times higher and in triplets 10 times higher than in singletons
Zygosity refers to the type of conception
Chorionicity denotes the type of placentation
Chorionicity rather than zygosity determines out outcomeZygosity and Chorionicity
Mechanism of dizygotic twinning
Fertilization of a single ovumSimilar sexGenetically identical
Fertilization of 2 separate ova
Monochorionic twinsWithin 72 hours (18-32%)3-8 days later (60-70%)
Monochorionic twins8-12 days later (1-2%)12-13 days later (0.5%)
Maternal responses
Cardiac output, GFR and renal blood flow Plasma volume by 1/3 > singletons Red cell mass 300 ml > singletons Hematocrit and hemoglobin Iron stores in 40% of women with twinsMultiple pregnancy
DiagnosisPatient profile:Etiological factors: positive past history and family history specially maternal, race, ageAssisted reproductive technologyEarly pregnancy:Hyperemesis, excessive weight gainminor complications of pregnancy such as backache, edema, varicose veins, hemorrhoids, striae, etc
Physical signsGeneral:Pallor, weight gain, excessive pedal edema/ varicose veinsPregnancy Induced Hypertension(PIH) and Pre-eclampsia (5-10times more)
Abdominal:Size > Date especially in midpregnancyMultiple fetal partsAuscultation of FHS: 2 different recordings by 2 observers and a difference > 10 bpm
Differential diagnosis
Elevation of the uterus by a distended bladderInaccurate menstrual history Hydramnios Hydatidiform moleUterine fibroidsA closely attached adnexal massFetal macrosomia (late in pregnancy)
Ultrasonography
Detect multifetal gestation 99% before 26 weeksConfirm fetal number [ 2 sacs or 2fetal heads in 2 perpendicular planes] Diagnose type and presentation and position and relation to each otherExclude congenital abnormalities/ conjoint twin
Maternal complicationsSymptoms hyperemesis, aches and pains of pregnancy worsenHypertensive disease of pregnancyPreterm deliveryPremature rupture of membranesPolyhydramniosPlacenta praeviaMalpresentationDelivery complications (operative delivery, placental abruption, cord accidents)Postpartum hemorrhage, depression
Fetal complicationsSpontaneous early pregnancy lossPrematurity Intra-uterine growth restrictionCerebral palsy - related to gestational age, 3 times in twins, > 10 times in tripletsIntrapartum traumaMonochorionic twins specific complications
Antenatal care
Routine booking investigationsFolic acid supplementationanemia treat immediatelySupport symptomatically
Serial growth scans :Dichorionic :4 weekly from 24 weeksMonochorionic : 2 weekly from 18 weeks- Liquor volume- Doppler study of umbilical artery
Intrapartum management
Presence of skilled obstetrician, anesthetist and neonatologist available at deliveryReliable intravenous accessCardiotocograph with dual monitoring capabilityPortable ultrasound scannerDelivery bed with lithotomy stirrupsObstetric forceps or vacuum apparatus active management of third stage: UterotonicsImmediate availability of bloodFacilities and staff for emergency cesarean section
Monochorionic Monoamniotic twins
3 - 12 x perinatal mortality10 x cerebral necrotic lesions
1% of monozygotic twins are monoamnionic Perinatal mortality rate of 30-50%, largely relates to a risk of intrauterine death before 32 weeks
Cord entanglement
Twin-Twin Transfusion Syndrome
Incidence : 4 - 20% of MC twins
It is characterised by an imbalance of blood flow between the twins
15 - 20% of perinatal deaths
Untreated, perinatal loss rates in the mid-trimester (80 - 100%)
Large volume amnioreduction
Amniotic Septostomy
Fetoscopic Laser Ablation
Delivery by Caesarean sectionat 34 weeks
Conjoined twins or Siamese twins
Anterior (thoracopagus)
Posterior (pygopagus)
Cephalic (craniopagus)
Caudal (ischiopagus)
Single intrauterine demise
2-6% of twins pregnancies
Up to 25% in MC twin pregnancy
Perinatal morbidity and mortality of the surviving co-twin - 19% perinatal death - 24% having serious long term sequelae
Treatment options
No optimal management
Prompt delivery -Iatrogenic prematurity risks
Conservative treatment -Subsequent handicaps
Intrauterine interventions
High order multiples
Perinatal risk increases exponentially with increasing number of fetuses
Multifetal pregnancy reduction (MFPR) at 10 to 12 weeks should be recommended for quadruplets and higher multiples
The situation with triplets is more controversial
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