Women carrying multiple gestations may be initially asymptomatic or may have normal signs and symptoms of pregnancy (eg, breast tenderness, fatigue, nausea, vomiting). Multiple gestations may be suspected in the setting of hyperemesis gravidarum or in a patient who has undergone assisted reproductive technology.

1. Multiple
Pregnancy
SAFA JEHANGIR KHAMISA

2. Introduction
• Refers to a pregnancy consisting of
multiple fetuses
• Predominantly twin pregnancies (97-99%
in the UK)
• Higher Order multiples refer to three or
more fetuses in one gestation.
2

3. Risk Factors
• Recent increase in use of assisted fertility
techniques (e.g. IVF – 1 in 5 successful in
UK)
• Increasing maternal age
• Maternal family history
• High parity
3

4. Classification
Multiple pregnancies can be categorized as follows:
• Number of fetuses: twins, triplets, quadruplets, etc.
• Number of fertilized eggs (Zygosity)
• Number of placentae (Chorionicity)
• Number of amniotic cavities (Amniocity)
4

5. Zygosity
• 1. Dizygotic:
• Non-identical
• Ovulation + fertilization of
two oocytes at a time
• Dichorionic (two
functionally separate
placentae)
• Diamniotic (separate
amniotic cavities)
• Can be same sex/different
sex
• Incidence: 70%
• 2. Monozygotic:
• Identical
• Single ovum fertilized
• Division of zygote post-
fertilization
• Incidence: 30%
5

6. Monozygotic varieties:
•Dichorionic diamniotic (DCDA): if the the zygote
divides immediately post-fertilization
•Monochorionic diamniotic (MCDA): if the zygote
takes 4-8 days post-fertilization to divide (incidence:
20%)
•Monochorionic monoamniotic (MCMA): if the
zygote takes between 8-12 days post-fertilization to
divide (incidence: 1%). In conjoined twins, the zygote
divides after 13th day of fertilization.

7. The "T sign" is really the absence of a twin-peak sign
(or lambda (λ) sign) and is used in ultrasound
assessment of a multifetal pregnancy. It refers to the
lack of chorion extending between the layers of the
intertwin membrane, denoting a monochorionic
pregnancy.
The lambda, or twin-peak, sign (the
triangular projection of chorionic tissue
extending into the intertwin membrane)
is one of the most useful ultrasound
signs for determining chorionicity in
early pregnancy

8. Incidence
8

9. Complications
9
The chances for complications in a multiple pregnancy are higher than those in a single
pregnancy. These include:
• Preterm birth (most common for DCDA)
• Fetal growth restriction (FGR)
• Cerebral palsy
• Stillbirth
Risks to the mother:
• Exaggerated ‘minor’ symptoms (nausea, vomiting, heartburn)
• Hypertension
• Thromboembolism
• APH
• PPH

10. Complications - Statistics
10
• Preterm delivery chances are higher in monochorionic pregnancies: 12% born before
viability, 25% born between 24-32 weeks
• Multiple gestations account for 20-25% of NICU admissions
• Perinatal mortality for monochorionic twins: 30/1000 (dichorionic: 3.8/1000)
• Overall infant mortality rate for multiple gestation: 5.5x higher than singletons.
• Still birth rate: 12/1000 births (twins), 31/1000 (triplets)
• 25% of twins may be lost in early pregnancy
• Fetal death of one twin in 2nd-3rd trimester causes labor (in dichorionic) or
handicap/death in survivor (monochorionic – 30% chance).

11. Complications – FGR
11
•Monitor and predict the severity of impaired fetal oxygen
•Select appropriate time for delivery
•Dichorionic pregnancy: 25% chance of one twin being small for
gestational age
•Monochorionic pregnancy: twice the chance as dichorionic
pregnancy of suboptimal fetal growth

12. 12
FGR – Management
Dichorionic pregnancy:
•If one fetus has FGR, elective preterm delivery must be avoided
•Chances of the healthy twin undergoing complications
•Avoid delivery before 28-30 weeks (despite chance of IUD of
FGR twin)
Monochorionic pregnancy:
•Death of first twin results in handicap of second twin
•Prolong pregnancy if below 30 weeks

13. 13
Twin-to-twin Transfusion Syndrome (TTTS):
•Specific to monochorionic twin pregnancies
•Occurs due to unbalanced vascular anastomoses
of the vessels of both twins
•MCDA: 10%, MCMA: 5%
Complications – TTTS

14. 14
TTTS – Pathophysiology
Physiological vascular connections:
1.Arteriovenous (AV)
2. Venoarterial (VA)
3. Aterioarterial (AA)
4. Venovenous (VV)
Pathology:
•Unbalanced connections –> more AV connection in one
direction than the other –> altered hydrostatic +
osmotic pressure
•AA anastomoses are protective (bidirectional nature –
corrects imbalance in intertwin blood flow)

15. 15
Ultrasound Criteria:
•Single placental mass
•concordant gender
•Oligohydramnios (with MVP <2cm) in one sac,
polyhydramnios (with MVP >8cm) in the other sac
•Discordant bladder
•Hemodynamic and cardiac compromise
TTTS – Diagnosis

16. 16
Stage I:
•Oligohydramnios + polyhydramnios sequence
•Bladder of donor twin visible
•Dopplers normal for both twins
Stage II:
•Oligohydramnios + polyhydramnios sequence
•Bladder of donor twin not visible
•Dopplers normal
TTTS – Quintero Staging

17. 17
Stage III:
•Oligohydramnios + polyhydramnios sequence
•Non-visualized bladder
•Abnormal Dopplers:
•absent/reversed end-diastolic velocity in umbilical artery
•Pulsatile flow in umbilical vein of either fetus
Stage IV
•One/both fetuses show signs of hydrops
Stage V:
•One/both fetuses have died

18. 18
Chronic TTTS – TAPS
Large inter-twin hemoglobin difference
•No oligohydramnios + polyhydramnios sequence seen
•Caused by residual unidirectional AV anastomoses
(without accompanying AA anastomosis)
•Leads to anemia in one twin and polycythemia in
second twin

19. 19
TTTS – Management
Prophylaxis:
• Serial ultrasound: every 2 weeks from 16w-24w
Treatment options:
• Tertiary referral
Treatment options:
•Expectant management
• Amnioreduction
• Septostomy
• Selective feticide
• Fetoscopic laser ablation of vascular anastomoses

20. 20
Fetoscopic Laser Ablation
Definitive treatment for severe TTTS (stage II and above)
from 16-26 weeks
•Above 26 weeks: delivery considered
Procedure:
•Local anesthetic + IV sedation / regional anesthesia / rarely
GA
•2-3mm diameter fetoscope introduced into amniotic cavity of
recipient twin guided by ultrasound
•Locate the dividing membrane between both amniotic
cavities at placental interface
•Ablate AV anastomoses through laser

21. 21
Complications – MCMA
Monochorionic monoamniotic twin pregnancy (MCMA):
•Associated with high morbidity and mortality
•Generally due to cord entanglement
•High risk of congenital anomalies: neural tube defects,
abdominal wall and urinary tract malformations
•20% chance of perinatal mortality

22. 22
MCMA – Management
• Regular ultrasounds (antenatal fetal surveillance)
• Delivery via C-Section (at 32-34 weeks)
• Hospitalization 28 weeks onwards
• Cardiotocography done several times daily, to
detect signs of cord compression

23. 23
Antenatal Care
Prerequisites:
• The woman’s needs and preferences must be considered
• Monoamniotic pregnancies should be given individual care
• Presence of a core team: obstetricians, midwives and ultra
sonographers
• Regular ultrasounds (for screening and FGR)
• Avoid corticosteroids
• Type of multiple pregnancy will help predict mode of delivery
• Lifestyle modification counselling must be given as normal
• Higher risk for anemia (CBC + iron, folic acid and B12
supplements regular)

24. 24
Antenatal Care
• At least 8 antenatal appointments
• Screening for HTN and DM
• Routine supplementation of folic acid
Screening:
o First trimester scan:
o Crown Rump Length: 45-84mm – 11+0w-13+6w. Indicates:
 Estimation of gestational age
 Determination of chorionicity (no. of placental masses + Lambda sign)
 Screening for Downs’ Syndrome
o Amniocentesis and CVS can also be done

25. 25
Anomaly scan:
o Multiple pregnancies have higher rates of congenital anomalies
o Usually only one fetus is affected
o Expectant management or selective feticide can be done
o If anomaly leads to handicap instead of death – parents need to
be counselled
o Anencephaly (a lethal anomaly) in one twin may be life-
threatening for the other twin
o Feticide is done via cord occlusion
o Chromosomal defects are also more common – couples must be
counselled accordingly

26. 26
Growth Assessments:
o Multiple pregnancies are at high risk for FGR
o Fetal weight monitoring must start at 20 weeks, every 4 weeks
o Tertiary referral needed when:
o Growth discrepancy of 25% or higher
o Discordant/abnormal fetal growth
o Fetal anomaly
o Discordant fetal death
o TTTS

27. 27
Delivery Plan
Clear delivery plan discussed and documented by third trimester:
o Mode of delivery
o induction plan (if needed)
o process of delivering each twin
o internal podalic version (if needed)
o risk of c-section
o complications post partum

28. 28
Intrapartum Management
While in labor:
•Continuous fetal heart monitoring (CTG)
•2 neonatal resuscitation trolleys ready
•2 obstetricians and 2 pediatricians ready
•NICU and Anesthetist on standby
•Oxytocin IV solution ready for augmentation of delivery of second
twin
•Oxytocin infusion (prophylactic for PPH)
•Portable ultrasound

29. 29
CTG – Twins (example)

30. 30
Mode of Delivery
Uncomplicated DCDA:
o Delivery at 37 weeks advocated
o vaginal delivery only if presenting twin is cephalic
o Risk of emergency C-section for second twin: 4%
o 40% chance of second twin being non-vertex – vaginal
delivery is safe
o If second twin is breech: breech must be fixed before
membrane rupture
o If second twin breech is transverse: external cephalic version
can be done (70% success rate)
o If ECV unsuccessful, do internal podalic version

31. Internal Podalic Version
o Identify fetal foot through intact membranes
o Grasp and pull the foot gently into birth canal
o Rupture membranes
o Easier with transverse lie
o Ultrasound guided (if limbs not located)

32. Mode of Delivery
Uncomplicated monochorionic pregnancy:
o Offer elective delivery at 36 weeks (after a course of
antenatal corticosteroids)
o 1.5% chance of late in-utero death for one or both twins
o Prolonging gestation beyond 38 weeks is contraindicated
(increased risk of intrauterine fetal death)

33. o Triplet pregnancies are now common in the UK
since the use of assisted fertility methods.
o Associated with high morbidity and mortality
o Down’s Syndrome risk calculation becomes
integral during first trimester screenings
o At least 11 antenatal checkups are mandatory
o Prolonging pregnancy beyond 36w is not
recommended
Higher Order Multiples

34. REFERENCES
• Obstetrics by Ten Teachers (20th edition)
• RCOG Guidelines – Monochorionic Twin Pregnancy Management
(https://www.rcog.org.uk/en/guidelines-research-
services/guidelines/gtg51/)
• Dr. Ziauddin Hospital Protocols and Guidelines – Department of
Obstetrics
Thank you