The Management of MC-DA twins .pptx

Management of MC-DA twins

1. Management of monochorionic twins

2. MONOCHORIONIC MINDED OBSTETRICIAN Determine monochorionicity (99 % in Ist trimester) Follow the protocols for serial scans ( you can not predict MCDA) Pick up complications at very early stage ( successful management) Counsel the parents as regards various options and their outcomes 2 You see what you search for Who can

3. Agenda 3 Introduction Types of Twin Pregnancies . What is monochorionic pregnancy Why MC pregnancies are different How to investigate Complications When to deliver Outcomes

4. Introduction

5. 3.1 % of live births are twins Multiple gestation pregnancies are inherently high risk to both the mother and the developing fetuses. Certain twin pregnancies, specifically those possessing a single chorion (monochorionic) , exhibit an even higher risk for numerous pre- and peri-natal complications. 50 % of twin pregnancies have PTL 10 % have second trimester miscarriage 1\3 of twin pregnancies have early fetal demise before 12 weeks Both twins survive in 85% of monochorionic pregnancies, only 1 survives in 7.5%, and neither survive in 7.5%. Eighty-five percent of monochorionic twins are born after 32 weeks, 5% before 28 weeks, and 10% between 28 and 32 weeks .

6. Types of twining​ The current classification of twins is oversimplified .

7. 7 There are 7 Types of Twin Pregnancy 1 - Identical twins : single zygote –genetically identical & both are of the same gender . 2 - Fraternal twins : 2 zygotes – genetically not identical - same\diff. gender -same\diff. bl groups . 3 - Half Identical \ sesquizygotic twins : 2 sperms fertilize one egg then split . The twins carried identical maternal genetic contributions, but only around half of the father’s DNA If one egg is fertilized by two sperms ,it results in three sets of chromosomes, one from the mother and two from the father. Three sets of chromosomes are typically incompatible with life and embryos do not usually survive. Sesquizygotic twins, the fertilized egg appears to have equally divided up the three sets of chromosomes into groups of cells which then split into two, creating the twins,” 4- Mirror image Twins : Early splitting also means that the twins are perhaps less identical than those who separate at the late blastocyst stage. Around a quarter of all identical twins are said to be mirror images of each other. This means that the left side of one twin exactly matches the right side of the other . 5- Mixed chromosomes twins \ Chimeric DZ : 2 sperms 2eggs – fusion – split ( heterokaryotyping – sample both fetuses) 6- Superfetation : Another pregnancy occurs during a pregnancy . 7- Superfecundation : 2 different fathers

8. WHAT IS THE MONOCHORIONIC TWIN PREGNANCY ?

9. Zygosity refers to the genetic makeup \ composition of the pregnancy . Twins , in rarer cases triplets, quadruplets(four), quintuplets (five), arising from a single fertilized ovum are termed monozygotic(MZ). The Dionne quintuplets . J. J. Beck et al. T wins or multiples originating from two or more ova that are fertilized by separate spermatozoa are called dizygotic (DZ) , or trizygotic in the case of triplets. Hall JG. Twinning. Lancet. 2003;362(9385): 735–43. Dizygotic twinning occurs when 2 ova are fertilized by separate spermatozoa spontaneously or as a result of ART. Each fertilized ovum develops independently ; therefore, there are 2 chorions, amnions, yolk sacs, and embryos. The process is the same for higher order multiples . Dichorionic twinning can result from dizygotic or monozygotic (fertilization of a single ovum) pregnancy. If a zygote splits within 3 days of conception, there is complete duplication of all cell lines with formation of chorions, amnions, yolk sacs, and embryos .This is the "best" type of monozygotic twinning in that the likelihood of 2 live births is highest 1\7 of dichorionic twins are monozygotic Monochorionic twins and ART Monochorionic twins represent 65% in spontaneous conceptions and 80% with assisted reproductive technology . Possible mechanisms for these differences include the practice of transferring day 5 blastocysts to improve pregnancy rates and manipulation of the zona pellucida in intra-cytoplasmic sperm injection . 1\3 of IVF pregnancies are twins

10. Zygocity refers to type of conception . Dizygotic (DZ) or nonidentical twins are result of multiple ovulations with 2 sperm fertilizing 2 ova . Monozygotic (MZ) or identical twins result from division of single zygote (1 sperm fertilizes 1 ovum) Chorionicity refers to type of placentation MZ pregnancies may be monochorionic (MC) or dichorionic (DC) depending on when zygote divides . DZ twins always have DC placentation (although can have "fused" placenta) Blastocyst Hatching is the term used when the  blastocyst cells start to break through the shell (zona pellucida) of the embryo .  It is a necessary step towards implantation and pregnancy The morula is a stage of post-fertilization development when a fertilized egg that is known as a single-celled zygote, transitions to a mass composed of around 10-30 cells. During in vitro fertilization (IVF), the morula phase typically occurs on day 4 of development post-fertilization. The morula phase is the final phase prior to blastocyst development Mc Namara et al.

11. MC Splitting 11

12. WHY MC TWINS ARE DIFFERENT ? Genetically identical hence, inherited disorders can affect both (risk as singleton pregnancies ) Placenta Placental Thrombosis Placental anastomosis ( unique complications ) Unequal placental share ( s- FGR ) Higher risk of complications ( PTL – 2 nd trimester miscarriage – early fetal demise ) 12

13. 13 Placenta The placenta is the black box of the intrauterine journey Placental Thrombosis Fetal vessel thrombosis is more common in monochorionic than in dichorionic placentas (5–8% vs. 3%) However, in dichorionic twins, vessel thrombosis is associated with hypertensive disorders, whereas in monochorionic twins, it is associated with growth restriction and even fetal demise. A thrombosis of an anastomosis may trigger an acute transfusion imbalance and therefore cause demise in a previously uncomplicated monochorionic pair.( unpredictable course)

14. 14 Vascular Anastomoses in Monochorionic Twin Placentas The monochorionic placenta is unique in that the placenta is shared by the two fetuses whose blood circulations are connected via placental vascular anastomoses. Vascular anastomoses can also be found in dichorionic placentas, but this occurrence is extremely rare ( few case reports of TTTS in DC twins ) Vascular anastomoses are the basis for the development of twin twin transfusion syndrome (TTTS) and twin anemia-polycythemia sequence (TAPS) There are three different types of vascular anastomoses: arterio-arterial (AA), veno -venous (VV), and arterio-venous (AV) anastomoses. AA and VV anastomoses are superficial, bidirectional, and have a low vascular resistance. AV anastomoses consist of an artery from one twin and the vein of the other twin that are connected by a capillary network below the chorionic plate. They can be visualized as a supplying artery and a draining vein that pierce the chorionic plate in close proximity to each other. As a result of the unidirectional flow in AV anastomoses, an imbalance in the net transfusion of blood can occur .

15. Both TTTS and TAPS develop from a net imbalance of blood flow through the vascular anastomoses. ( volume shift) D ifferences in the placental angioarchitecture, number and size of anastomoses, and therefore in the amount and direction of blood flow, resulting in different clinical presentations and complications . A A anastomosis is protective (Number and diameter) V V anastomosis is risk factor A smaller diameter of the AA anastomosis (with a higher vascular resistance) may prevent adequate equilibration of the intertwin hemodynamic imbalances, hence leading to the development of TTTS

16. TAPS placentas are characterized by the presence of only few miniscule AV anastomoses. On average, spontaneous TAPS placentas have only 4–5 anastomoses compared to 10 in uncomplicated monochorionic placentas, whereas post-laser TAPS placentas have even fewer residual anastomoses (on average 2 per placenta) . The diameter of these tiny anastomoses is <1 mm and makes it difficult for unexperienced eyes to be able to detect them, especially without careful dye injection. The small size and small number of these anastomoses is the basis of the pathogenesis of TAPS as it allows only a very slow transfer of blood from the donor to the recipient and does not lead to the associated amniotic fluid imbalance as seen in TTTS . Placentas in Twin Anemia-Polycythemia Sequence (TAPS) Placentas in Twin-Twin Transfusion Syndrome (TTTS) TTTS is described as resulting from a net imbalance of blood flow between the fetuses through communicating placental anastomoses. TTTS only develops in the presence of unidirectional AV anastomoses, when blood from one twin (the donor) is pumped through the artery to the shared cotyledon and then drains through a vein to the other twin (the recipient). TTTS develops therefore in the presence of at least one AV anastomosis, unless blood is pumped back to the donor through another AV anastomosis in the opposite direction or through a bidirectional AA or VV anastomosis

17. Monoamniotic placentas are characterized by the high prevalence of large AA anastomoses (in 98% of cases) and VV anastomoses (in 43% of cases), as well as proximate cord insertions in the majority of cases (defined as a distance between the two cords is ≤4 cm) . The frequent presence of a large AA anastomosis in monoamniotic placentas may explain the low risk of TTTS or TAPS in monoamniotic twins (<5%). Placentas in Monoamniotic Twins Superficial artery-to-artery placental anastomosis providing perfusion of the acardiac twin by the donor (pump) twin . (shown on Doppler ultrasound by reversal of the acardiac twin umbilical arterial blood, i.e. flow towards the fetus ) TRAP Sequence

18. Placentas in Selective Fetal Growth Restriction ( sFGR ) Velamentous Cord Insertion A velamentous cord insertion is also three times more common in twins than in singletons and is especially prevalent in monochorionic (20%) as compared to dichorionic (8%) twins. In monochorionic twins, a velamentous insertion also increases the risk of growth restriction and intra-uterine demise sFGR results primarily from unequal placental sharing. The growth-restricted fetus often has a small placental share and a velamentous cord insertion, while the larger fetus has a larger placental share and a (para-) central cord insertion. Placental characteristics in sFGR vary according to the type and severity of sFGR . Vasa Previa About 1 in 25 pregnancies with velamentous cord insertion have vasa previa, and 90% of pregnancies with vasa previa have a velamentous insertion . V elamentous insertions are more common in twin pregnancies . V asa previa (defined as within a 5 cm of the internal os ) should be ruled out at the time of the second-trimester scan. I n a dichorionic twin pregnancy, we should also exclude a velamentous insertion of the second twin’s cord on the intertwin septum, as this may behave as vasa previa during a vaginal twin birth

19. See you after Friday prayer 20

20. How to investigate 21 First trimester (appearing twin , vanishing twin , NT & MCDA , Chorion city ,dating , NIPT and labelling ) Invasive testing ( amniocentesis for both sacs for discordant growth ,discordant anomaly) 2 nd & 3 rd Trimester Monoamniotic twins

21. 22 First Trimester : Viability, gestational age, chorionicity and amnionicity should be assessed between 11 and 13 6 weeks gestation in all multiple pregnancies In spontaneously conceived pregnancies, it is recommended using the larger of the two crown rump lengths to estimate gestational age . . 2 yolk sac .. MCDA 1 yolk sac.. MOMO x It is not easy to identify thin intervening amnion before 8 weeks The Appearing Twin More common in MC twins Scan prior to 6 weeks more than 80% of MC twins are classified as singleton and 11 % of DC Twins are classified as singleton. The vanishing Twin The vanishing twin syndrome (VTS) is used to describe the spontaneous loss of one developing embryo early in a multiple pregnancy. NIPT --- 10 weeks

22. 23 Chorionicity If chorionicity cannot be con fi dently established sonographically , pregnancies should be monitored as if they were monochorionic Examination of placental membranes by ultrasound imaging serves as a non - invasive method for determining zygosity/twin status . Chorionicity is identified in 98 % of cases in first trimester by T sign . Between 15 to 20 weeks decreases 10 % per week Extension of chorionic tissue between membranes T-sign T he dogma of a single chorion being synonymous with monozygosity is no longer proper due to chimeric DZ twins , a phenomenon in which one individual is composed of cells from two or more zygotes . Umstad MP et al. 2012

23. 24 NT & MCDA pseudo-risk for the whole pregnancy Use average NT ( screening depends on maternal age + NT only ) 75% DR at 5% FPR cfDNA - NIPT Heterokaryotyping The difference in chromosomal makeup between twins of a monochorionic pair is known as hetererokaryotypic monochorionic twinning and is only picked up by an amniocentesis of both sacs. Heterokaryotypic monochorionic twins can be mosaic. Here, errors in early mitotic cell division such as nondisjunction and anaphase lagging may give rise to two different cell lines. Dating of pregnancy : IVF pregnancy : use embryo transfer date Natural conception : use CRL of larger twin

24. 25 Labelling Twins should be labelled on antenatal ultrasound according to their lateral (right/left) or vertical (top/bottom) orientation, rather than their proximity to the cervix, and, ideally, that labelling should be maintained across all subsequent ultrasound examinations .

25. In all twin pregnancies, cervical length should be assessed, either transabdominally or transvaginally , at the time of the anatomical ultrasound scan and, ideally, once more at around 23 - 24 weeks gestation. All monochorionic pregnancies should undergo ultrasound surveillance every 2 weeks from 16 weeks gestation until delivery to detect twin to twin transfusion syndrome, twin anaemia polycythaemia sequence and selective fetal growth restriction. Ultrasound assessment of all monochorionic twins from 16 weeks onwards should include measurement of growth (fetal biometry), fetal bladder filling, and the single deepest pocket of amniotic fluid on both sides of the membrane, as well as umbilical and middle cerebral artery peak systolic velocity Doppler studies for each fetus 2 nd & 3 rd Trimester

26. Monoamniotic Twins Ultrasound features of monoamniotic twins include the absence of a dividing amniotic membrane, a single placenta, close proximity of placental cord roots, concordant sex and, commonly, cord entanglement .

27. MCDA Complications 28 TTTS 10% TAPS 4-5% MC \ 9-13 % TTTS TRAP 2.5 % Single fetal demise Discordancy ( growth – anomaly – amniotic fluid )

28. 29 Twin Twin Transfusion Syndrome TTTS Definition: TTTS is a serious complication affecting approximately 10% - 15% of monochorionic twin pregnancies. It is caused by unbalanced (predominantly arteriovenous) placental vascular anastomoses . Diagnosis: All women with monochorionic pregnancies should be advised to report any sudden increase in abdominal distension or dyspnoea . Ultrasonographic diagnosis of TTTS is based on the following criteria: 1. Signi fi cant AFV discordance, with oligohydramnios (DVP < 2 cm) in the donor ’ s sac and polyhydramnios in the recipient ’ s sac (DVP > 8 cm before and > 10 cm after 20 weeks gestation). 2. Discordant bladder sizes, with a subjectively small or empty fetal bladder in the donor and a distended (or rapidly cycling at earlier gestations) bladder in the recipient . Owing to lower fetal blood volumes in early pregnancy (i.e. < 16 - 17 weeks), a DVP > 6 cm in this period may represent “ polyhydramnios ” in the recipient, as urine output is limited and the recipient ’ s bladder may be rapidly cycling, rather than being persistently distended .

29. In absolute anhydramnios , both layers of amnion are completely approximated, and the donor may appear to be dangling from the placenta or uterine wall by a thin stalk (the “ cocoon ” sign . EFW discordance, with sFGR in the donor, may often be present, representing the often simultaneous occurrence of TTTS and placental discordance. However, the presence of EFW discordance is not necessary to make a diagnosis of TTTS. Haemodynamic and cardiac compromise in the form of abnormal UA PI, MCA PSV and/or DV Doppler and development of (predominantly right-sided) cardiac dysfunction in the recipient twin leading to non-immune hydrops are not essential criteria for a diagnosis of TTTS, but do determine its staging. Cervical length should also be assessed by ultrasonography to determine the possible need for cerclage and to assist in counselling patients about the risk of preterm delivery and neonatal death (predicted in one series by a cervical length < 16 mm).

30. Cardiac dysfunction is commonly seen in the recipient twin in TTTS. Cardiac function determines the urgency of the need for laser and, to some degree, the ef fi cacy of treatment Quintero Staging system Functional pulmonary stenosis or atresia, ranged from 11% If TTTS is suspected, at a minimum, the DV waveform should be assessed as a marker of fetal right heart dysfunction an absent or reversed DV a wave, signi fi cant tricuspid regurgitation, a monophasic tricuspid in fl ow pattern, and ultimately functional pulmonary stenosis or atresia, all of which can be reversed following successful placental laser treatment of TTTS

31. Management of Twin e Twin Transfusion Syndrome Fetoscopic laser ablation of placental vascular anastomoses is the fi rst-line treatment for TTTS, rather than amnioreduction or septostomy. The Eurofetus randomized controlled trial (RCT) demonstrated that fetoscopic laser ablation of placental anastomoses between 16 and 26 weeks gestation increased the survival rate of one twin at 6 months of age and decreased the incidence of periventricular leukomalacia and neurological complications, when compared with the cohort treated with serial amnioreduction. O verall survival following laser for TTTS is about 65% e 70% for both twins and about 85% - 90% for at least one twin. Neurodevelopmental impairment has been reported in about 8% e 10% of cases following laser treatment and is predominantly related to prematurity. Preterm premature rupture of membranes before 34 weeks gestation occurs in about 7% - 8% of cases following laser treatment Outcome of Twin - Twin Transfusion Syndrome The Quintero staging system serves as a prognostic indicator following treatment for TTTS .. A t least one neonate survived in 91% of cases at stage I, 83% of cases at stage II, 67% of cases at stage III, and 50% of cases at stage IV. The Solomon laser technique decreases the risk of twin - twin transfusion syndrome recurrence and twin anaemia polycythaemia sequence

32. TWIN ANAEMIA-POLYCYTHAEMIA SEQUENCE TAPS Diagnosis of Twin Anaemia-Polycythaemia Sequence (TAPS) TAPS is characterized by a signi fi cant discordance in haemoglobin values in monochorionic twins, without necessarily a signi fi cant discordance in AFV and is caused by the presence of miniscule ( < 1 mm) arteriovenous placental vascular anastomoses, without compensatory larger artery-to-artery (A-A) anastomoses TAPS should besuspected antenatally if a high MCA PSV (1.5 MoM),suggestive of fetal anaemia , is found in one fetus and a low MCA PSV (0.8 MoM), suggestive of polycythaemia , is found in the other, often in the absence of signi fi cant AFV discordance. Alternatively, MCA PSV discordance 1 MoM can be used to make the diagnosis of TAPS TAPS occurs spontaneously in approximately 4% - 5% of monochorionic twins, typically developing later in pregnancy than TTTS (usually after 24 - 26 weeks); however, it has rarely been described in the fi rst trimester). TAPS can also co-exist with TTTS. TAPS has been Reported in 9-13% of cases following fetoscopic laser ablation for TTTS .

33. A difference in placental echogenicity may also be evident in TAPS, with a thicker, hyperechoic portion belonging to the anaemic donor and a thinner, hypoechoic portion belonging to the recipient. A “ starry sky ” liver is apparent in the recipient twin. Severe neurodevelopmental impairment was detected in 9% of TAPS survivors overall (18% of donors vs. 3% of recipients , and bilateral deafness was identi fi ed in 15% of donors vs. 0% of recipients

34. The incidence of iatrogenic TAPS decreases signi fi cantly when the “ Solomon ” technique, which aims to “ dichorionize ” the placenta, is used with fetoscopic laser to coagulate a continuous line along the placental equator by “ joining the vascular ablation dots Management of Twin Anaemia-Polycythaemia Sequence That MCA PSV measurement be part of the routine (every 2 weeks) monitoring for all Monochorionic twin pregnancies from 16 w eeks gestation onwards A double intrauterine death would be extremely rare in TAPS, as exsanguination into the demised twin would be unlikely, owing to the tiny anastomoses. A neonatal blood transfusion is needed in the fi rst 24 hours in 60% - 80% of anaemic donors, and recipients may be severely polycythaemic , with 40% - 70% requiring an urgent partial exchange transfusion to haemodilute , as severe hyperviscosity can lead to skin necrosis, limb ischaemia , or severe cerebral injury with resultant neurodevelopmental impairment SERIAL IUT – LASER ABLATION

35. TWIN REVERSED ARTERIAL PERFUSION SEQUENCE (TRAP) TRAP sequence occurs in about 2.5% of monochorionic twin pregnancies. Its pathognomonic ultrasonographic feature is the presence of an acardiac mass, perfused by An anatomically normal “ pump ” twin, with retrograde perfusion from the pump twin to the acardiac twin through an A-A anastomosis A morphous, usually edematous, acardiac twin , which is retrogradely perfused via a placental artery-to-artery anastomosis by its healthy “ pump ” co-twin

36. Cause of death: High-output cardiac failure in the “ pump ” twin, secondary to its hyperdynamic circulation. Phenotypes: The phenotype ranges from a fetus with well-developed lower extremities, pelvis and abdomen to an amorphous tissue mass that is not readily recognizable as having any fetal parts . First Trimester TRAP is typically diagnosed in the fi rst trimester and must be excluded, whenever a single intrauterine death is suspected in twins, by using colour Doppler, which would demonstrate a reverse fl ow velocity pattern in cases of TRAP. If managed conservatively, the risk of demise in the “ pump ” twin is approximately 30% by 18 weeks gestation. Poor prognostic factors include an increased ratio between the abdominal circumferences of the acardiac and “ pump ” twins, polyhydramnios and/or cardiovascular compromise in the “ pump ” twin. If the acardiac : “ pump ” twin ’ s AC ratio is 50%, urgent intervention is recommended. 1 Interstial laser is the most feasible technique European School - Will intervene whatever the TRAP volume As they found 3 in 4 baby’s have delivered with a postnatal neurodevelopmental delay especially when the intervention was done after 23 weeks gestation . -The best time to intervene is 18 to 23 weesks Whenever the death of one monochorionic twin is diagnosed early in pregnancy, colour Doppler ultrasonography should be used to exclude twin reversed arterial perfusion sequence, by con fi rming the absence of blood fl ow in the suspected demised twin

37. Single Fetal Demise After the spontaneous death of one monochorionic twin, surveillance for fetal anaemia by middle cerebral artery peak systolic velocity measurement should be instituted rapidly , as anaemia correlates with the risk of a hypotensive neurological injury . The surviving twin may bene fi t from intrauterine transfusion . Fetal neurosonography and, ideally, MRI should be used to identify any potential cerebral injury; however, ultrasonographic evidence of injury may take 3-4 weeks to develop after the death of the co-twin Monoamniotic twins are at high risk of cardiac abnormalities and should undergo a detailed anatomical ultrasound with particular emphasis on fetal cardiac evaluation If Single IUD of Fetus in Second Trimester – Chance of Preterm(24-32 wks ) Delivery -54%. If Selective Termination in Second Trimester – Chance of Preterm Delivery(24-32 wks ) is More than 54%. Co twin demise 12 -25 % Neurological sequuelae 18 -25 %

38. Twins never allowed to go beyond 38 weeks Risk of maternal complications is high ( preeclampsia \ GD \ PROM PRTERM DELIVERY When to Deliver Monoamniotic twins should be monitored closely from viability onwards (either as out-patients or in-patients) and should undergo an elective caesarean delivery at approximately 33 weeks gestation Uncomplicated DC twin delivered at 37 weeks

39. To conclude : Thank You

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48. Navigating Q&A sessions Know your material in advance​ Anticipate common  questions​ Rehearse your responses Maintaining composure during the Q&A session is essential for projecting confidence and authority. Consider the following tips for staying composed:​ Stay calm​ Actively listen​ Pause and reflect​ Maintain eye contact 50

49. Speaking impact​ Your ability to communicate effectively will leave a lasting impact on your audience​ Effectively communicating involves not only delivering a message but also resonating with the experiences, values, and emotions of those listening 51

50. Dynamic delivery​ Learn to infuse energy into your delivery to leave a lasting impression​ One of the goals of effective communication is to motivate your audience Metric​ Measurement​ Target​ Actual​ Audience  attendance​ # of attendees​ 150​ 120​ Engagement duration​ Minutes​ 60​ 75​ Q&A interaction​ # of questions​ 10​ 15​ Positive  feedback​ Percentage (%)​ 90​ 95​ 52

51. Final tips & takeaways​ Consistent rehearsal​ Practice makes perfect, so strengthen your familiarity with the presentation​ Refine delivery style​ Pacing, tone, and emphasis​ Timing and transitions​ Aim for seamless, professional delivery​ Practice audience Enlist colleagues to listen & provide feedback​ Seek feedback​ Reflect on performance​ Explore new techniques​ Set personal goals​ Iterate and adapt 53

52. Speaking engagement metrics​ Impact factor​ Measurement​ Target​ Achieved​ Audience interaction​ Percentage (%)​ 85​ 88​ Knowledge retention​ Percentage (%)​ 75​ 80​ Post-presentation surveys​ Average rating​ 4.2​ 4.5​ Referral rate​ Percentage (%)​ 10​ 12​ 54

53. THANK YOU Brita Tamm​ 502-555-0152​ [email protected]​ www.firstupconsultants.com