This document discusses twin pregnancies and provides information on: 1. The types of twins based on chorionicity and zygosity. 2. The maternal and fetal complications that can occur in twin pregnancies including preeclampsia and preterm birth. 3. The diagnosis and management of twin pregnancies including ultrasound examination and increased surveillance of monochorionic twins.

1. Twinpregnancy
-DR.DIVYA JAIN

3. Terms
• Zygosity refers to the type of conception
– Two thirds of all twins are dizygotic.
• Chorionicity denotes the type of placentation.
*Chorionicity rather than zygosity determines
outcome.

4. TWINS
DIZYGOTIC
2/3
MONOZYGOTIC
1/3
Monochorionic monoamniotic <1%
Monochorionic diamniotic -75%
Dichorionic diamniotic -25%
Dichorionic
Diamniotic

8. SUSPICION OF TWIN PREGNANCY
 History
• h/o IVF, taking ovulation inducing drugs
 Symptoms
• Early pregnancy : excessive nausea, vomiting, Abnormal bleeding
• Mid pregnancy : excessive weight gain, uterus larger than date
• Late pregnancy : pressure symptoms – dyspnea, dyspepsia
 Signs
• Anemia, edema, high BP, abnormal weight gain
• Uterus larger than date
• Multiple fetal poles felt
• 2 distinct FH heard

9. DIAGNOSIS
Before 10 weeks sonographic findings to
determine chorionicity depends upon number
of
• gestational sacs
• yolk sacs.

10.  1. Number of Gestational Sacs
 Each gestational sac forms its own placenta and
chorion:
 gestational sacs: DC twin
 1 gestational sac with 2 identified heartbeats: MC twin
 Number of Yolk Sacs
 2 yolk sacs are seen in the extra-embryonal coeloma:
diamniotic
 1 yolk sac in most cases indicate monoamniotic twins

11. After 10 weeks
These sonographic signs are no longer present:
gestational sacs are no longer distinctly
separable, and the inter-twin membrane is
formed
Diagnosis depends upon
• Placental number
• Chorionic peak sign
• Membrane characteristics.

12.  Number of Distinct Placentas-
 1placental mass: MC
 2 distinct, separate placentas: DC
Careful sonographic examination may help distinguish a single
placenta from 2 placentas in abutment.
 Presence or Absence of the Chorionic Peak (twin peak or
lambda sign)-
Projecting zone of tissue of similar echotexture to the placenta
Triangular in cross-section and wider at the chorionic surface of
the placenta, extending into, and tapering to a point within, the
inter twin membrane.
Most often identifies DC
MC: absence of the twin peak sign.

13.  Inter-Twin Membrane Characteristics
DC :
2 layers of amnion and 2 layers of chorion.
Thicker > 2 mm
MC: ≤ 2mm

14. If a membrane is not detected: careful evaluation to diagnose
or exclude monochorionic monoamniotic twinning
Possibilities:
1.Monoamniotic twinning
2.Twin with complete oligohydramnios (stuck twin)
ABSENT MEMBRANE IN A MONOAMNIOTIC TWIN

17. LAMBDA SIGN

18. MONOCHORIONIC & DIAMNIONIC
T SIGN

20. MATERNAL COMPLICATIONS
Antepartum
hyperemesis
hydramnios

21. Pre eclampsia(3 fold times),eclampsia(6 fold times)
Pressure symptoms
Anaemia
Antepartum hemorrhage-
Placenta previa
Abruption

22. Intrapartum complications
Dysfunctional labour
Malpresentations
Increased chance for operative delivery
Post partum hemorrhage
Retained placenta

23. FOETAL COMPLICATIONS
I. Prematurity

24. 2.DISCORDANT GROWTH
• Fetal growth differs slightly in twin gestations and twin specific
charts may be used to define the normal growth rate. Precision may
also be obtained by using sex and race specific charts.
• In clinical practice, however, these differences are small and
singleton growth curves may be used. Patterns of fetal growth are
more important than absolute measurements. Both must be
interpreted in the light of the clinical history, together with all the
genetic and environmental factors that may affect fetal growth.
• The diagnosis of discordance has been based on the following:
• • AC difference of 20 mm (sensitivity of 80%, specificity 85%, PPV=
62%)
• • EFW based on bi-parietal diameter (BPD) and AC or AC and femur
length (FL) > 20 percent (sensitivity 25-55%)

25. • Discordant fetal growth can be due to different genetic growth
potentials, structural anomaly of one fetus, or an unfavourable
placental implantation.
• True discordance is an indicator for an increased risk of IUGR,
morbidity, and mortality for the smaller twin.
• A risk for aneuploidy, anomaly or viral syndrome affecting only
one fetus must also be considered when discordant growth is
identified.

26. • USG monitoring of growth within a twin pair is
mainstay in management .
• The indication for delivery should take into
consideration of the fetal well-being, the gestational
age and serial growth velocity
MANAGEMENT

27. 3. Single fetal demise
monochorionic
Death of one twin
Shift of blood
Normal
twin
25% risk of co-twin death /25% risk of neurological
damage in surviving twin(FOETAL DEATH SYNDROME)

28. • 2-6% of twins pregnancies
• Perinatal morbidity and mortality of the surviving co-twin
19% perinatal death
24% having serious longterm sequelae
• Morbidity of surviving fetus depend on chorionicity and
consequences of prematurity

29. 4. Cord entanglement
• Cord entanglement occurs in over 70% of MCMA twins and is
believed to be the major cause for sudden IUFD
• Ultrasound diagnosis of cord entanglement and close fetal
surveillance from 24 weeks onward, may help to improve
perinatal outcome.
• Because of the high perinatal mortality, prophylactic delivery by
caesarean section at 32 to 34 weeks is recommended

30. 5. TWIN-TWIN TRANSFUSION SYNDROME
• Features of TTTS are the result of hypoperfusion of the donor twin
and hyperperfusion of the recipient twin.
• Oligohydramnios develops in the amniotic sac of the donor twin.
• Profound oligohydramnios can result in the stuck twin
phenomenon in which the twin appears in a fixed position against
the uterine wall.
• Either twin can develop hydrops fetalis.
• The donor twin can become hydropic because of anemia and high-
output heart failure.
• The recipient twin can become hydropic because of hypervolemia.
• The recipient twin can also develop hypertension, hypertrophic
cardiomegaly, disseminated intravascular coagulation, and
hyperbilirubinemia after birth

32. Uss of TTS….STUCK TWIN

34. TREATMENT FOR TTTS
• Amniotic septostomy
• Laser ablation
• Selective fetocide
• Serial amnioreduction

35. Serial amnioreduction
survival 64% overall, 74% of at least one twin

36. Laser ablation
(55% overall survival—73% of at least one twin),

37. 6.Acardiac foetus
Normal fetus/pump twin
Minimal oxy. extracted by lower
part of Acardiac fetus
A-A anastamoses
in placenta
De oxygenated
blood
Umb
.A
Umb. A
Fully de oxygenated
Upper part of fetus ,no growthUmb.VV-V anastomoses
in placenta
Umb.V

39. 7. Vanishing twin
Cessation of cardiac activity in a
previously viable foetus
Foetus papyraceous…

40. 8.Conjoint twins
Always monozygotic
Classification-
Thoracopagus
Craniopagus
ischiophagus
pyophagus
omphalopagus

41. • Rare complication of monoamniotic twining,
with an incidence of around 1: 55 000
pregnancies.
• Accurate prenatal diagnosis is possible in the
first trimester and allows better counseling of
the parents regarding the management
options.

42. Dichorionic twins
• Ultrasound at 10–14 weeks: (a)
viability; (b) chorionicity; (c) NT:
aneuploidy
• Structural anomaly scan at 20–22
weeks.
• Serial fetal growth scans e.g 24,
28, 32 and then two- to four-
weekly.
• 34–36 weeks: discussion of mode
of delivery and intrapartum care.
• Elective delivery at 37–38
completed weeks. Some by
40weeks
• Postnatal advice and support
(hospital- and community-based)
to include breastfeeding and
contraceptive advice
Monochorionic twins
• Ultrasound at 10–14 weeks: (a)
viability; (b) chorionicity; (c) NT:
aneuploidy/TTTS
• Ultrasound surveillance for TTTS
and discordant growth: at 16
weeks and then two-weekly.
• Structural anomaly scan at 20–22
weeks (including fetal ECHO).
• Fetal growth scans at two-weekly
intervals until delivery.
• 32–34 weeks: discussion of mode
of delivery and intrapartum care.
• Elective delivery at 36–37
completed weeks (if
uncomplicated).
• Postnatal advice and support
(hospital- and community-based)
to include breastfeeding and
contraceptive advice.
ANTENATAL CARE

43. PRESENTATION
• 40% of twins present as vertex/vertex,
• 35% as vertex/non-vertex,
• remaining 25% of twins present with the
leading twin in a non-vertex presentation at
birth .

45. MANAGMENT
Basic Principles-
• The presence of skilled obstetrics attendants for
labor and delivery
• Anesthesiologist available
• Neonatal care personnel sufficient for
resuscitation of the newborns
• Reliable IV access
• CTG

47. If the second twin is in non-vertex presentation, the other
options include
o Assisted vaginal breech delivery or breech extraction,
o Internal podalic version following by breech extraction,
o ECV followed by vaginal cephalic delivery,

48. Indications for Caesarean Section-
Elective-
• First twin non-cephalic
• Conjoined twin
• Monoamniotic twin
• Placenta previa
• Previous LSCS
• IUGR in dichorionic twin
• Congenital abnormality
Emergency-
• Fetal distress
• Cord prolapse of 1st twin
• Non progress of labor
• 2nd twin transverse after delivery of 1st twin

49. MANAGEMENT DURING LABOUR
1st stage-
• Good intrapartum care : blood, IV access,
continuous FHS monitoring.
• In case of inefficient uterine contractions,
oxytocin augmentation can be used.
• The criteria for diagnosing slow progress are
the same as in singletons.

50. SECOND STAGE OF LABOUR
• Following delivery of the first twin, ergometrine must NOT be given as
it might facilitate the premature placental separation before the
delivery of the second twin.
• The cord of the first twin should be clamped and divided as usual.
• After delivery of the 1st twin, the obstetrician should ascertain the lie
and presentation of the 2nd twin.
• Once a Cx presentation is confirmed, the decent of the fetal head is
expected with re-establishment of uterine contractions.
• Oxytocin infusion should be commenced if uterine contractions have
failed to resume.
• Fetal heart rate should be continuously monitored.
• A twin-to-twin delivery interval of ≤ 30 minutes, after which delivery
should be expedited, since the risks of both acidosis and second stage
Caesarean section increase with the length of this interval

51. THIRD STAGE
• increased risk of primary PPH.
• After delivery of the shoulder of the 2nd
twin, active management of the third stage
should ensue.
• Oxytocin infusion in addition is advised.
• The placentas should be examined as a
routine to confirm the chorionicity and
amnionicity.