Multiple gestation pregnancies are increasing in incidence due to assisted reproductive technologies and delayed childbearing. These pregnancies are at higher risk for maternal and fetal complications including hypertension, preterm birth, and growth discordance between twins. Prenatal surveillance includes regular ultrasounds to monitor fetal growth, well-being, chorionicity, and complications like twin-twin transfusion syndrome. Mode of delivery depends on fetal presentation, with vertex-vertex twins usually aiming for vaginal delivery while other presentations may require cesarean. Higher-order multiples generally require cesarean delivery for safety.

1. MULTIPLE GESTATION

2. Incidence
• 33.2 per 1000 total births in the US
• Increasing incidence
• Assisted reproductive technologies
• Advanced maternal age at childbirth

3. Maternal Morbidity
1. Hypertension and placental abruption
2. Preterm labor
3. Preeclampsia
4. HELLP syndrome
5. Anemia
6. PPROM
7. GDM
8. Acute fatty liver
9. Chorioendometririts
10. Postpartum hemorrhage

4. MATERNAL ADAPTATIONS
1. Serum progesterone
2. Estradiol, estriol
3. hPL
4. hCG
5. AFP
Higher than in singleton gestations

5. MATERNAL ADAPTATIONS
↑ Heart rate and stroke volume
↑ Cardiac output and cardiac index
Mean maternal blood pressures at term are significantly higher
Plasma volume increases by 50%-100%→ 𝑫𝑰𝑳𝑼𝑻𝑰𝑶𝑵𝑨𝑳 𝑨𝑵𝑬𝑴𝑰𝑨
Further increase in tidal volume and oxygen consumption ---
more alkalotic arterial pH

6. • Recommendations for maternal weight gain
• Normal weight 37 – 54 lb
• Overweight 31 - 50 lb
• Obese 25 - 42 lb

7. ULTRASONOGRAPHY IN MULTIPLE GESTATION
1. Confirming a diagnosis of multiple gestation
2. Chorionicity
3. Fetal anomalies
4. Guiding invasive procedures
5. Fetal growth
6. Measuring cervical length
7. Fetal well being
8. Preparing for delivery

8. DIAGNOSIS OF MULTIPLE GESTATION
• 5 weeks - Multiple gestational sacs with yolk sacs
• 6 weeks- with cardiac activity

9. CHORIONICITY
• Best performed in the 1st trimester
• DICHORIONIC
- clearly separate gestational sacs, each surrounded by a thick
echogenic ring before 8 weeks gestation
MONOCHORIONIC
- separate echogenic rings are not visible

10. • DIAMNIONIC
2 fetal poles with 2 yolk sacs in a monochorionic gestation
• MONOAMNIONIC
2 fetal poles and 1 yolk sac

11. Detection of fetal anomalies
• 83% rate of detecting fetuses with Down syndrome in twin
pregnancies achieved by combining risks derived from maternal age
and nuchal translucency thickness measurement at 10-14 weeks
• Finding of increased nuchal translucency in one fetus of a
monochorionic pair may predict the development of TTTS

12. Evaluation of fetal growth
• Serial ultrasonography
-most accurate method to assess fetal growth in cases of
multiple gestation
Weight discordance
-indication for close fetal surveillance rather than indication for
immediate delivery
> 20 % important predictor for adverse perinatal outcomes

13. Measurement of cervical length
• Can identify those at increased risk for preterm delivery
• Done every 2 weeks from 16- 24 weeks gestation
• Major limitation:
• Lack of proven effective intervention when a short cervix is noted

14. Confirmation of fetal well being
1. Biophysical profile
2. Doppler velocimetry
3. Amniotic fluid volume
a. a single overall AFI without reference to the dividing membrane
b. Individual AFI for each sac
c. largest two-diameter pocket in each sac
d. subjective assessment of the relative distribution of fluid between sacs

15. ANTEPARTUM MANAGEMENT
Fetal surveillance
-serial ultrasound every 3-4 weeks from 18 weeks gestation in
dichorionic twins or every 2 weeks if growth restriction or
growth discordance is discovered.
-for monochorionic twins, serial growth scans are performed
every 2 weeks from 16 weeks gestation

16. Indications for NST with BPP
1. Significant growth restriction in either fetus
2. Growth discordance (>18%)
3. Oligohydramnios
4. Decreased fetal movement
5. Maternal medical complications

17. FETAL SURVEILLANCE
Growth discordance
• Twice-weekly NST
• BPP
• Umbilical artery Doppler velocimetry
If absent or reversed end-diastolic flow is discovered, delivery should be
considered if gestational age is sufficiently advanced

18. INTRAPARUM MANAGEMENT
• TIMING OF DELIVERY
38 weeks- nadir of perinatal mortality for dichorionic twins
All twin fetuses should be delivered by 39 weeks of gestation because
of the rising morbidity and mortality beyond that date

19. Intrapartum management
PREPARATIONS
Prostaglandins- for induction of labor
Oxytocin- for induction or augmentation
VBAC
- No randomized studies that confirm the safety of VBAC in multiple
gestation
- Requires multidiscpilinary cooperation:
- OB and nursing staff
- Anesthesiologist
- At least one neonatologist or pediatrician
Intravenous access and prompt availability of blood products

20. INTRAPARTUM MANAGEMENT
• Ultrasound should be performed as soon as possible after admission
to determine fetal presentation
• Electronic fetal monitor should be available
• Continous Lumbar Epidural anesthesia is strongly recommended if
trail of labor is chosen
• Vaginal delivery should be performed in an operating room because
CS may be required for the second twin in a small number of cases

21. VERTEX-VERTEX TWINS
• Occurs in 40-45% of all twin pregnancies
• In the absence of obstetric indications, vaginal birth should be
planned regardless of gestational age
• No absolute indication to deliver the second twin within a specified
time limit
• Active intervention to complete the delivery is encouraged by studies
that link length of interval to fetal acid-base status

22. VERTEX-NONVERTEX TWINS
• Occurs in 35-40% of all twin pregnancies
• Mode of delivery depends on:
1. Size of the second twin
2. Presence of growth discordance
3. Availability of obstetric staff skilled in breech delivery, internal podalic
version and total breech extraction
-the adverse perinatal outcome associated with breech second twin is more
often related to prematurity or growth restriction rather than the mode of
delviery

23. Vertex- nonvertex twins
• Vaginal delivery can be offered for the nonvertex second twin if the
estimated fetal weight is 1500-3500 grams provided it is not
significantly larger than the 1st twin and the head is not
hyperextended

24. NONVERTEX FIRST TWIN
• Occurs in 15-20% of all twin pregnancies
• Almost always managed by Cesarean delivery because of concerns
about interlocking fetal heads

25. HIGHER-ORDER MULTIPLE
GESTATIONS
• Cesarean delivery under regional anesthesia is recommended
because of the difficulties in adequately monitoring three or more live
fetuses that are of a viable gestational age in labor and through
delivery

26. ASYNCHRONOUS DELIVERY
• Delivery of one fetus in a multiple gestation that is not followed
promptly by birth of the remaining fetus
• Acceptable only in the management of extreme prematurity
• CONTRAINDICATIONS
• Monochorionicity
• Intramnionic infection
• Placental abruption
• Co-existence of preeclampsia

27. TWIN-TWIN TRANSFUSION SYNDROME
• Occurs exclusively in monochorionic twin pregnancies
• imbalance in blood flow through the vascular communications in the
placenta, which leads to overperfusion of one twin and
underperfusion of its co-twin

28. TTTS: Clinical and Sonographic Features
DONOR
• Hypoperfused
• IUGR
• Oligohydramnios/anhydramnios
• Stuck twin appearance
• Lower hematocrit
• EKG: no specific finding
RECIPIENT
• Hyperperfused
• Hypertensive
• Biventricular hypertrophy
• Diastolic dysfunction
• Polyhydramnios
• EKG: ventricular hypertrophy
and dilation, TR and cardiac
failure

29. TWIN-TWIN TRANSFUSION SYNDROME:
ULTRASONOGRAPHIC CRITERIA
1. Single placenta
2. Sex concordance
3. 20% growth discordance
4. Oligohydramnios and polyhydramnios
5. Umbilical cord size discrepancy
6. Presence of fetal hydrops or cardiac dysfunction
7. Abnormal umbilical artery Doppler findings

30. QUINTERO STAGING
Stage I: Donor twin bladder visible, fetal Doppler values normal
Stage II: Donor twin bladder not visible, fetal Doppler values normal
Stage III: Donor twin bladder not visible, fetal Doppler values critically
abnormal
Stage IV: Hydrops
Stage V: Intrauterine death of one or both fetuses

31. TWIN-TWIN TRANSFUSION SYNDROME:
Management
1. Serial reduction amniocenteses
2. Amniotic septostomy
3. Selective fetoscopic laser coagulation

32. Selective fetoscopic laser coagulation

33. TWIN ANEMIA POLYCYTHEMIA SEQUENCE
(TAPS)
• Middle cerebral artery peak systolic velocity (PSV) > 1.5 MoM in one
fetus (anemic ex-recipient), and
• PSV < 0.8 MoM in the other fetus (polycythemic ex-donor fetus)
• May occur in 13% of cases of TTTS treated with laser and
spontaneously seen in 5% of monochorionic twins that had never
been diagnosed with TTTS

34. TWIN ANEMIA POLYCYTHEMIA SEQUENCE
(TAPS)
Management:
1. preterm delivery
2. Intrauterine fetal transfusion
3. Selective fetocide
4. Repeat fetscopic laser coagulation

35. MONOAMNIOTIC TWINS
• Single amniotic sacs containing both twins
• 1% of monozygotic twins
• Increased perinatal risk
• Premature delivery
• Growth restriction
• Congenital anomalies
• Vascular anastomosis between twins
• Umbilical cord entanglement

36. MONOAMNIOTIC TWINS
Management
SULINDAC
-Prostaglandin inhibitor that decrease AFV
→stabilize fetal lie and reduce the risk for cord
entanglement
-only intervention proposed to reduce cord accidents
Daily NST
-beginning at 24-26 weeks to determine the frequency of
variable deceleration

37. TWIN REVERSED ARTERIAL PERFUSION
SEQUENCE (TRAPS)

38. TWIN REVERSED ARTERIAL PERFUSION
SEQUENCE (TRAPS)
• Acardiac twinning
• A unique abnormality of monochorionic multiple gestations
• One twin has an absent, rudimentary/non-functioning heart
• 1% of monozygotic twin
• Occurs because of early 1st trimester circulatory failure of one fetus in
a monochorionic twin pregnancy, together with the development of
arterioarterial or venovenous anastomoses between the umbilical
arteries of both fetuses

39. TWIN REVERSED ARTERIAL PERFUSION
SEQUENCE (TRAPS)
Management:
fetoscopic surgery- cord interruption at 16-18 weeks,
before features of cardiac decompensation develop

40. CONJOINED TWINS
• Subset of monozygotic twin gestation which incomplete embryonic division
occurs 13-15 days after conception
• 1.5/100,000 births
• Prenatal diagnosis:
-failure to visualize two fetuses separately in what appears to be a
single amniotic sac
-BIFID APPEARANCE OF THE 1ST TRIMESTER FETAL POLE
-MORE THAN 3 UMBILICAL CORD VESSELS
-HEAD PERSISTENTLY AT THE SAME LEVEL AND BODY PLANE
-FAILURE of the fetuses to change position relative to each other over
time

41. CONJOINED TWINS
CLASSIFICATIONS
1. Thoracopagus
2. Omphalopagus
3. Pyopagus
4. Ischiopagus
5. Cranioagus

42. CONJOINED TWINS
• Expectant management
Fetal echocardiography and MRI to delineate exact extent of union and assist in
neonatal surgical planning
Classical Cesarean section – delivery method of choice to minimize maternal
and fetal trauma

43. INTRAUTERINE DEMISE OF ONE FETUS
• Common during the 1st trimester
• At 12 weeks gestation, can result in profound neurologic injury and
increased risk of SGA in the surviving fetus
Neurologic injury occurs because of the significant hypotension at the
time of death of the co-twin

44. THANK YOU