Multiple pregnancy: Aboubakr Elnashar

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  • Protocol for management of Multiple pregnancy Aboubakr Elnashar Benha university Hospital, Egypt
  • Sources: SOGC, 2011 NICE, 2012
  • Types of twin pregnancy 1. Dichorionic: (DC) Each baby has a separate placenta. 2. Monochorionic diamniotic: (MC DA) Both babies share a placenta but have separate amniotic sacs. 3. Monochorionic monoamniotic: (MC MA) Both babies share a placenta and amniotic sac.
  • Splitting in first 3 d after fertilization: Diamniotic, Dichorionic pregnancy Splitting between d 3 and 9: Diamniotic, Monochorionic pregnancy Splitting between d 9 and 12: Monoamniotic, Monochorionic pregnancy Splitting after the 12th d: Conjoined twins
  • Types of triplet pregnancy 1. Trichorionic: Each baby has a separate placenta and amniotic sac. 2. Dichorionic triamniotic: One baby has a separate placenta and two of the babies share a placenta. All three babies have separate amniotic sacs. 3. Dichorionic diamniotic: One baby has a separate placenta and amniotic sac and two of the babies share a placenta and amniotic sac. 4. Monochorionic triamniotic: All three babies share one placenta but each has its own amniotic sac. 5. Monochorionic diamniotic: All three babies share one placenta. One baby has a separate amniotic sac and two babies share one sac. 6. Monochorionic monoamniotic: All three babies share a placenta and amniotic sac.
  • A. Antenatal I. Determining g age and chorionicity II. ANC III.Fetal complications: screening IV.Maternal complications: screening V. PTL: prediction and prevention VI.Indications for referral to fetal medicine centre B. Delivery I. Timing of delivery II. Mode of delivery III. Vaginal delivery IV. CS
  • I. Determining g age and chorionicity US: when CRL: 45 mm to 84 mm (11-14 W) A. Estimate g age B. Determine chorionicity C. Screen for Down's syndrome Use the largest baby to estimate g age {avoid the risk of estimating it from a baby with early growth pathology}. When twin pregnancy is the result of IVF, accurate determination of gestational age should be made from the date of ET. (II-1A)
  • B. Determine chorionicity using 1. Number of placental masses 2. Lambda or T-sign 3. Membrane thickness. Assign nomenclature to babies (upper and lower, or left and right) and document this clearly in the woman's notes to ensure consistency throughout pregnancy. After 14 w 0 days, determine chorionicity As above plus discordant fetal sex. If TAS are poor {retroverted uterus or a high BMI}: TVS to determine chorionicity. Do not use 3DUS to determine chorionicity.
  • Dichorionic Diamniotic twin: a triangular projection of chorionic tissue emanating from fused dichorionic placentas and extending between layers of the intertwin membrane. < 20 w Preferably< 14 W
  • dichorionic twin in the first trimester: a thick intertwin membrane 16 and 24
  • Monochorionic Twins: a thin intertwin membrane 16 and 24 Monochorionic Twins (20%). (One placenta) T sign
  • II. ANC Multidisciplinary team: 1. Specialist obstetricians 2. Ultrasonographers 3. Foetal medicine Referrals center
  • 1. Information and emotional support Explain aims and possible outcomes of all (screening and diagnostic) tests {minimise anxiety}. 2. Diet, lifestyle and nutritional supplements Same as in routine ANC. Higher incidence of anaemia CBC At 2024 w {identify who need early supplementation with iron or folic acid At 28 w: as in routine ANC
  • 3. Frequent AN visits combined with US First CRL measures from 45 mm to 84 mm (11- 14 w) MC: every 2 to 3 w, starting at 16 w DC: every 3 to 4 w, starting from the anatomy scan (18 to 22 weeks) (II-1)
  • III. Fetal complications Information about screening Before and after every screening test. . 1. Screening for Down's syndrome 2. Screening for structural abnormalities 3. Screening for feto-fetal transfusion syndrome 4. Screening for IUGR
  • 1. Screening for Down's syndrome Why: {greater likelihood of Down's syndrome in twin and triplet pregnancies} When CRL measures from 45 mm to 84 mm (11-14 W) How: Map the fetal positions Use the combined screening test: Nuchal translucency HCG, Pregnancy-associated plasma protein-A (PAPPA) calculate the risk of Down's syndrome
  • A thickened nuchal translucency of 3.3 mm
  • 2. Screening for structural abnormalities Cardiac abnormalities between 18 and 22 w (II-2B) 45 minutes for the anomaly scan
  • 3. Monitoring for feto-fetal transfusion syndrome Start diagnostic monitoring at 16w. Repeat monitoring fortnightly until 24 w. Weekly monitoring if intertwin membrane infolding or amniotic fluid discordance
  • Incidence: 15% of MC Pathology: In MC placenta: vascular anastamoses. Superficial and deep. 1) arterioarterial (AA) 2) arteriovenous (AV), or 3) venovenous (VV).
  • Blood from a donor twin is transferred to a recipient twin: growth-restricted discordant donor twin markedly reduced AF: "stuck."
  • Diagnosis Early 1. Recipient: Increased nuchal translucency Abnormal Doppler of DV 2. Folding of intertwin membrane can at 16w. Late: 1. Recient: Polyhydramnios An enlarged fetal bladder 2. Donor: oligohydramnios Severe oligohydramnios: amniotic membrane is closely applied to the fetus, which lies apposed to the uterine wall (stuck twin). bladder can be barely visible
  • . Recepient: 1. Increased NT 2. Abnormal Doppler of DV Inter-twin membrane folding
  • Donor Twin Severe Oligohydramnios Recipient Fetus Polyhydraminos
  • .Stuck twin
  • Inter-twin membrane folding (arrow = dividing membrane) Polyhydramnios in g sac A and oligohydramnios in g sac B (arrow = dividing membrane)
  • 4. Monitoring for IUGR Growth curves As Singleton 30 min for growth scans Start at 20 w undertake scans at intervals of less 4w. Estimate f Wt discordance using two or more biometric parameters Growth discordance: either Difference (20 mm) in AC or Difference of 20% EFW. (II-2) Consider a 25% or greater difference in size between twins or triplets as a clinically important indicator of IUGR
  • AFV: deepest vertical pocket oligohydramnios when < 2 cm polyhydramnios when > 8 cm. (II-2B) Umbilical artery Doppler should not be routinely offered in uncomplicated twin pregnancies. (I-E) Do not use umbilical artery Doppler US to monitor for IUGR or birth weight differences in twin or triplet pregnancies. Umbilical artery Doppler may be useful in the surveillance of twin gestations when there are complications involving the placental circulation or fetal hemodynamic physiology. (II-2)
  • Discordant growth A 20% difference in f weights or AC difference of > 20 mm There is a 2.5 cm difference in the AC measurements for twin A and twin B, indicating 2nd trimester growth discordancy
  • IV. Maternal complications Hypertension 1. Measure BP and test urine for proteinuria {screen for hypertensive disorders} at each ANV 2. 75 mg of aspirin daily from 12 w until the birth of the babies if they have one or more of the following risk factors for hypertension: first pregnancy age 40 years or older pregnancy interval of more than 10 y BMI of 35 kg/m2 or more at first visit family history of PET.
  • V. Preterm birth 1. Prediction women with twin pregnancies have a higher risk of PTL if they have had PTL in a previous singleton pregnancy. Do not use cervical length (with or without fetal fibronectin) routinely to predict the risk
  • 2. Prevention Do not use the following interventions (alone or in combination) : bed rest at home or in hospital IM or vaginal progesterone cervical cerclage oral tocolytics.
  • 3. Untargeted corticosteroids Do not use single or multiple untargeted (routine) courses of corticosteroids {no benefit in using untargeted administration of corticosteroids}.
  • VI. Indications for referral to a tertiary level fetal medicine centre 1. MC MA twin pregnancies 2. MC MA triplet pregnancies 3. MC DA triplet preg