Multiple pregnancies can involve twins, triplets or more. Monitoring of monochorionic twins is important due to risks of twin-twin transfusion syndrome (TTTS), twin anemia-polycythemia sequence (TAPS), twin reversed arterial perfusion (TRAP) sequence, and selective growth restriction (sGR). TTTS occurs in 10-15% of monochorionic twins due to uneven blood flow through connecting blood vessels and can be diagnosed and treated with laser ablation. SGR can occur without fluid imbalance and is detected by significant fetal growth differences and abnormal Doppler readings of the umbilical artery. Close ultrasound monitoring every 2 weeks from 16 weeks is recommended for monochorionic twins.

1. Multiple Pregnancy
Ryan Saktika Mulyana

2. Multiple Pregnancy/ Multifetalpregnancy
The presence of more than one fetus in the gravid
uterus is called multiple pregnancy
• Two fetuses (twins)
• Three fetuses (triplets)
• Four fetuses (quadruplets)
• Five fetuses (quintuplets)
• Six fetuses (sextuplets)

3. INCIDENCE
Hellin’s Law:
Twins: 1:89
Triplets: 1:892
Quadruplets: 1:893
Quintuplets: 1:894
Conjoined twins: 1 : 60,000

4. Demography
• Race: most common in Negroes
• Age: Increased maternal age
• Parity: more common in multipara
• Heredity - family history of multifetal gestation
• Nutritional status – well nourished women
• ART - ovulation induction with clomiphene
citrate, gonadotrophins and IVF

5. Superfecundation
Fertilization of two different ova released in
the same cycle
Superfetation
Fertilization of two ova released in different
cycles

6. Monozygotic (1/3 rds)
Results from fertilization
a single ova
Monozygotic twins
(syn: Identical, uniovular)
Dizygotic (2/3 rd)
Results from fertilization
of of two ovum
Dizygotic twins
(syn: Fraternal, binovular)
Types of twins

7. Monozygotic twins (syn: Identical, uniovular):
• Upto 3 days - diamniotic-dichorionic
• Between 4th & 7th day - diamniotic
monochorionic - most common type
• Between 8th & 12th day- monoamniotic-
monochorionic
• After 13th day - conjoined / Siamese twins.

9. DIZIGOTIC TWINS

10. MONOZIGOTIC TWINS

12. Conjoined twins
Ventral:
1) Omphalopagus
2) Thoracopagus
3) Cephalopagus
4) Caudal/ ischiopagus
Lateral:
1) Parapagus
Dorsal:
1)Craniopagus,
2)Pyopagus

13. THORACOPAGUS
ISCHIOPAGUSCRANIOPAGUS
RACHYPAGUSPYOPAGUSOMPHALOPAGUS

14. Born May 11, 1811
Samutsongkram, Siam (now Thailand)
Died January 17, 1874 (aged 62)
Mount Airy, North Carolina, U.S.
Cause of death Stroke
Heart attack
Resting place White Plains Baptist Church Cemetery
Citizenship Siamese
American
Occupation Cotton Plantation
Years active 1834-1874
Chang and Eng Bunker

15. INVESTIGATION

16. Chorionocity

17. Differences in zygocity
Monozygotic
• 1 ova + 1 sperm
• Same sex
• Identical features
• Single or double placenta
• Same genetic features
• DNA microprobe -same
Dizygotic
• 2 ova + 2 sperm
• Same or opposite sex
• Fraternal resemblance
• Double or s/t fused
• Different genetic features
• DNA microprobe - different

18. Differences in chorionicity with single placenta
D / D ( fused placenta )
• Monozygotic or dizygotic
• Thick dividing membrane
> 2mm
• Twin peak / lambda sign
M / D
• Monozygotic
• Thin dividing membrane
2mm or less
• T sign
Chorionicity should be determined at the time the twin pregnancy is detected by
ultrasound based upon the number of placental masses, the appearance of the membrane
attachment to the placenta and the membrane thickness. This scan is best performed
before 14 weeks of gestation.[New 2016] (B)

22. On ultrasound, the fetuses in twin pregnancies should be assigned
nomenclature (i.e. upper andlower, or left and right) and this should be clearly
documented in the woman’s case notes to ensureconsistency throughout
pregnancy. [New 2016] (C)

23. Dating

24. Dating
When twin pregnancy is the result of IVF, accurate
determination of gestational age should be made from the
date of embryo transfer. (II-1A)
Toavoid missing a situation of early IUGR in one twin, most
experts agree that the clinician may consider dating
pregnancy using the larger fetus. (III-C)

25. Screening for Abnormality

26. Aneuploidy Screening in 1st T
Nuchal transluscency and maternal age.
 Using the average NT:
NT in conjunction with maternal age: 75% sensitivity
 Useful in the early detection or prediction of TTTS.
An NT threshold at the 95th percentile had a
PPV:43%
NPV: 91%
Women with monochorionic twins who wish to have aneuploidy screening should be offered
nuchal translucency measurements in conjunction with first trimester serum markers
(combined screening test) at 11+0 weeks to 13+6 weeks of gestation (crown–rump length 45–
84 mm). [New 2016] (C)

27. Aneuploidy Screening in the 2nd T
Soft markers of Down syndrome
 Nonossified nasal bone
 linear arrangement of the tricuspid and mitral valves within the heart
 thickened nuchal skin fold
 slightly short humerus relative to head size
 slightly short femur relative to head size
 echogenic intracardiac focus
 fetal hydronephrosis
In women with monochorionic twin pregnancies who ‘miss’ or who have unsuccessful first
trimester screening for aneuploidy, second trimester screening by the quadruple test should be
offered. [New 2016] (D)

28. Congenital Malformations
 Incidence:
 1.2 to 2 times more common in twin.
 Dizygotic twins
 Rate/fetus is the same as in singletons
 Monozygotic twins
 rate is 2 to 3 times higher.
 The most common structural abnormalities
 cardiac
 neural tube and brain
 facial clefts
 gastrointestinal
 anterior abdominal wall
All monochorionic twins should undergo a routine detailed ultrasound scan between 18 and
20+6 weeks of gestation which includes extended views of the fetal heart anatomy (as
recommended in the Fetal Anomaly Screening Programme screening of a singleton fetus). (C)

30. Screening for Preterm Birth

31. How:
Cervical length
When:
21-24 w
{correlates highly with PTL at < 32 to 33 w}
 Risk of PTL is increased 3- to 5-fold from baseline prevalence.
 PPV: 22% to 38 %.
 NPV: high: 94% to 96%.
CL > 35 mm at mid 2nd T: probability of reaching 34-35w is quite high (88% -98%).
Rate of cervical shortening
 2.5 mm/w predicted PTL (positive likelihood ratio of 10.8).
 Progressive shortening greater than expected may indicate a higher risk of PTL.

32. There is still insufficient data to recommend screening twin
pregnancies with TVS cervical length, but this might change soon!
(Schuit et al. 2014)

34. Assesment of Fetal Growth

36. Assesment of Fetal Well Being

37. RCOG recommendation
• Fetal ultrasound assessment should take place every 2 weeks in uncomplicated
monochorionic pregnancies from 16+0 weeks onwards until delivery (D)
• At every ultrasound examination, liquor volume in each of the amniotic sacs should be
assessed and a deepest vertical pocket (DVP) depth measured and recorded, as well as the
umbilical artery pulsatility index (UAPI). Fetal bladders should also be visualised. (Appendix
III). [New 2016] (GPP)
• From 16+0 weeks of gestation, fetal biometry should be used to calculate an estimated fetal
weight (EFW) and the difference in EFW calculated and documented. As the risk of selective
growth restriction (sGR) extends to delivery, this should be performed at 2-weekly intervals
until delivery. [New 2016] (D)

38. COMPLICATION

39. Maternal Complications
During pregnancy
 Miscarriages
 Hyperemesis gravidorum
 Anaemia
 Pre-eclampsia (25%)
 Hydramnios ( 10 % )
 GDM ( 2 – 3 times)
 Antepartum hemorrhage – placenta previa and placental abruption
 Cholestasis of pregnancy
 Malpresentations
 Preterm labour (50%) twins – 37 weeks, triplets – 34 weeks, quadruplets – 30 weeks
 Mechanical distress such as palpitation, dyspnoea, varicosities and haemorrhoids
 Obstructive uropathy

40. During Labour:
 Prelabour rupture of the membranes
 Cord prolapse
 Incoordinate uterine contractions
 Increased operative interference
 Placental abruption after delivery of 1st baby
 Postpartum haemorrhage
During puerperium:
 Subinvolution
 Infection
 Lactation failure

41.  Preterm delivery
 IUGR
 Congenital Abnormalities
 Cord abnormalities :
 Single umbilical artery
 Velamentous insertion
 Cord entanglement
 Cord prolapse
 Monochorionic twins :
 Discordant growth
 Twin to twin syndrome
 Single fetal Demise
Fetal Complications

42. MONOCHORIONIC
DIAMNIOTIC TWIN

43. • Both babies share one placenta
• 1/3 of twins in the UK have MC placentas Recent
increase in multiple pregnancies due to ART
• Particular challenges: vascular placenta anastomoses that are
almost universal and connect umbilical circulation of both twins
All women with a twin pregnancy should be offered an ultrasound
examination between 11+0 weeks and 13 +6 weeks of gestation
(crown–rump length 45–84 mm) to assess fetal viability, gestational age
and chorionicity, and to exclude major congenital malformations (B)

46. If unable to determine chorionicity, treat as
monochorionic until proven otherwise

50. Subsequent Management
Aim
◦ Timely detection of TTTS
◦ Detection of other complications such as selective
IUGR,TOPS,TRAPS, single fetal demise

51. TTTS

52. • 95% monochorionic placentas have these but only 10-
15% suffer adverse outcomes
• TTTS and TRAP are the most well recognised
complications
• Suggested aetiology: deep anastomoses within
placental mass are usually btwn arteries and veins
which allow unidirectional blood flow
Screening for TTTS by first trimester nuchal translucency measurements should not be offered.
[New 2016] (C)
Screening for TTTS should be by ultrasound examination from 16+0 weeks onwards, at 2-weekly
intervals, noting and recording fetal biometry and liquor volumes (DVP). Fetal bladders should
also be visualised.

54. TTTS

55. ARTERY VS VEIN ANASTOMISIS

56. DIAGNOSIS TTTS

57. STAGE TTTS

58. PROGNOSIS TTTS

59. In severe early TTTS, the prominent feature is
discordant liquor
Growth may not be significantly
affected in early pregnancy

60. Management options of early severe TTTS
Amnioreduction
Septostomy
Selective laser ablation of communicating vessels

61. Amnioreduction
• Amnioreduction: survival rates 60-65%
• Septostomy: decrease in need to rpt procedure and
survival rate similar, however risk of inter-twin cord
entanglement
• Laser ablation: most logical therapeutic approach,
placental vessels traced endoscopically from origins and
ablate all anastomoses, survival rate 70-81%,consider in
ALL stages of TTTS to improve perinatal outcome

62. Recommendation (RCOG)
Severe TTTS presenting < 26 weeks should be treated by laser
ablation rather than amnioreduction or septostomy Little
information about maternal morbidity after laser (A)
Delivery of monochorionic twin pregnancies previously complicated
by TTTS and treated should be between 34+0 and 36+6 weeks of
gestation. [New 2016] (D)

63. Complications of laser ablation
Most common: PROM (9%)
Placental abruption 1%
Miscarriage 8%
NICE March 2006

65. TAPS (Twin Anaemia Polychytemia Sequence)

67. • Monochorionic Twin (5%)
• Spontaneous or after incomplete Laser
treatment for TTTS
• Same pathology as TTTS (Milder form)
• Large intertwin hemoglobin differences in the
absence of amniotic fluid discordances
• Usually in 3rd trimester.

68. Presence of arterial-arterial anastomoses is protective against TTTS
In TAPS: either less A-V anastomoses or more A-A
anastomoses
TAPS should be screened for following fetoscopic laser ablation for TTTS and in
other complicated monochorionic pregnancies requiring referral to a fetal medicine
centre (such as those complicated by sGR) by serial middle cerebral artery peak
systolic velocity (MCA PSV). [New 2016] (GPP)

69. TAPS: Antenatal Diagnosis
No apparent growth and liquor discordance
Main feature: discordance in MCA blood flow
MCA Peak systolic velocity measurement
(PSV)
– Moderate to severe anemia : PSV MoM > 1,5
– Polycythaemia: PSV MoM < 0.8
Even in apparently uncomplicated MCDA, it is advised
to do MCA doppler in every patient after 24 weeks

71. TRAPS (Twin ReversedArterialPerfusionSequence)

72. • Also called acardiac twinning
• High perinatal mortality of the normal ‘pump’ twin due to
CCF and hydrops
• Treatment:
– Expectant
– Cord occlusion of the acardiac twin if show evidence of
heart failure in the pump-twin

73. PUMP TWIN
ACARDIAC TWIN

75. Selective Growth Restricted (sGR)

76. • Differentiate from TTTS by absence of
polyhydramnios in one of the amniotic sacs,
although the small twin may have
oligohydramnios owing to placental insufficiency
• Scans after 24 weeks to detect fetal growth
restriction

77. Discordant Growth*
• Abdominal Circumference difference >20 mm
• EFW difference > 20%** (Larger twin as a reference)
• BPD > 6 mm
• FL > 6 mm
* Usually accompanied with abnormal UA doppler
** Latest evidence suggests that difference by 18% is significant
At each scan from 20 weeks of gestation (at 2-weekly intervals) onwards, calculate EFW discordance
using two or more biometric parameters. Calculate percentage EFW discordance using the following
formula: ([larger twin EFW – smaller twin EFW]/larger twin EFW) x 100. Liquor volumes as DVP should
be measured and recorded (to differentiate from TTTS). [New 2016] (C)

78. Umbilical artery Doppler evaluation in monochorionic twins with sGR allows definition of prognosis and
potential morbidity. In particular, those with absent or reversed end-diastolic velocities (AREDV) and
‘cyclical’ umbilical artery Doppler waveforms (intermittent AREDV) are at increased risk of perinatal
mortality and morbidity (Appendix IV). [New 2016] (C)

79. In type I sGR, planned delivery should be considered by 34–36 weeks of
gestation if there is satisfactory fetal growth velocity and normal umbilical
artery Doppler waveforms. [New 2016] (GPP)
In type II and III sGR, delivery should be planned by 32 weeks of gestation,
unless fetal growth velocity is significantly abnormal or there is worsening of
the fetal Doppler assessment. [New 2016] (GPP)
Abnormal ductus venosus Doppler waveforms (reversed flow during
atrial contraction) or computerised cardiotocography short-term
variation should trigger consideration of delivery. [New 2016]

80. Why is MCDAdifferent compared to DCDA?
• Death in one twin may lead to death of the other twin
• Neurological sequelae in surviving twin
Importance of close monitoring and timely decision for delivery!!!
• try to achieve good survival of both fetuses
• at least survival of one fetus with minimal neurological sequelae
In cases of early-onset sGR in association with poor fetal growth
velocity and abnormal umbilical artery Doppler assessments,
selective reduction may be considered an option. [New 2016] (C)

81. Single fetal demise

82. Risks are not restricted to MC pregnancies with a prior diagnosis
of TTTS
Caused by acute haemodynamic changes around time of death, as
survivor haemorrhaging part of its circulating volume into the
circulation of the dying twin leading to hypotension and low
perfusion and eventually ischaemic end organ damage
After a single fetal death in a monochorionic pregnancy, clinicians should be
aware that the risks to the surviving twin of death or neurological abnormality
are of the order of 15% and 26%, respectively. [New 2016] (B)

83. Tromboplastin Release
Thrombotic Arterial Occlusion of anterior & Middle
Cerebral arteries
Multicystic Ensephalomalacia

84. Detailed counselling and record in case notes
Rapid delivery is unwise unless there are significant CTG
abnormalities or evidence of anaemia in the survivor
(MCA doppler) or if fetal death occurs late in pregnancy
Evidence of fetal compromise could represent
continuing damage to the brain and other organs,
therefore conservative management is often
appropriate

85. Plan for brain imaging by 4 weeks to establish whether serious
cerebral morbidity has occurred as such manifestation on CNS are
variable and takes up to 4 weeks to occur
Fetal MRI provides earlier and more detailed information about brain
lesions than USG
Fetal magnetic resonance imaging of the brain may be performed 4 weeks
after co-twin demise to detect neurological morbidity if this information would
be of value in planning management.(D)

86. Intervention to prevent concordant fetal demise or
neurological sequelae?
• If single fetal demise is diagnosed early: intrauterine fetal blood
transfusion of the surviving twin may be considered
Fetal anaemia may be assessed by measurement of the fetal MCA PSV using
Doppler ultrasonography. (D)

87. Early in pregnancy:
prognosis for the surviving fetus is excellent.
2nd and 3rd T
2% to 5% of twin pregnancie

88. Timing of delivery
Deliver at 36-37, does not appear to be a/w increased risk of
serious adverse outcomes
Appropriate to aim for vag birth unless there are accepted, specific
clinical indications for CS eg twin one lying breech or previous CS
60% of twins: spontaneous birth before 37 weeks
Prolonging pregnancy beyond 38 weeks increases risk
of fetal death
If elective birth declined, offer weekly appointment with specialist
obstetrician, offer USG at each visit and perform biweekly
biophysical profile assessments, fortnightly fetal growth scans

89. Sequels of Death of Co-twin DC MC
Fetal Demise 3% 15%
Preterm Birth 54% 68%
Abnormal Postnatal Cranial Imaging 16% 34%
Neuro-developmental Impairment 2% 26%
Management depends on
1. Chorionicity
2. Gestation age
3. Time since death.

90. MCDA: its all about discordance!!
TTTS
Discordant liquor
Selective IUGR
Discordant growth
TAPS
Discordant MCA PSV
discordant fetal anomaliesTRAPS/discordant fetal
anomalies

91. Assessment in uncomplicated
monochorionic twin pregnancy

92. Timing and mode of delivery in
uncomplicated monochorionic pregnancies
optimal timing and method of delivery for
otherwise uncomplicated monochorionic pregnancies
(without TTTS, sGR or TAPS)
Women with monochorionic twins should have timing of birth discussed and
be offered elective delivery from 36+0 weeks with the administration of
antenatal steroids, unless there is an indication to deliver earlier. [New 2016]
(C)
It is appropriate to aim for vaginal birth of monochorionic diamniotic
twins unless there are other specific clinical indications for caesarean
section.(A)

93. MONOCHORIONIC
MONOAMNIOTIC TWIN

95. Cord entanglement

96. MCMA twins almost always have umbilical cord entanglement when
visualised using colour flow Doppler. Such a finding has not consistently
been demonstrated to contribute to overall morbidity and mortality. [New
2016] (D)
MCMA twins have a high risk of fetal death and should be delivered by
caesarean section between 32+0 and 34+0 weeks. [New 2016] (D)
specific problems of MCMA pregnancies and how should they
be managed