Multiple Gestation

Question 1

What is multiple pregnancy?

Answer 1

presence of more than one fetus in the uterus at the same time

Question 2

Categories of multiple pregnancies?

Answer 2

Depending on the number of fetuses categorized into
1. Twins (most common)
2. Triplets
3. Quadruplets

Question 3

Epidemiology of multiple pregnancies?

Answer 3

• Rates increasing, globally constituting 3% of live births
• Assisted fertility (rate directly proportional to number of embryos transferred)
• Advanced maternal age

Question 4

Complication of multiple pregnancy?

Answer 4

• Associated with higher rate of both maternal and fetal complication compared to singleton
• Incidence varies
  > Japan 6/1000 births
  > Nigeria 40/1000 births

Question 5

Classifications of multiple pregnancy?

Answer 5

Classification based on
1. Number of fetuses (twins, triplets, quadruplets)
2. Number of fertilized eggs: Zygosity
3. Number of placentae: Chorionicity
4. Number of amniotic cavities: Amnionicity

Question 6

Dizygotic vs monozygotic?

Answer 6

Dizygotic - 70%
Monozygotic - 30%

Question 7

Dizygotic?

Answer 7

• 2 separate ova fertilized by separate sperms
• Always Dichorionic diamniotic
• Thick separating membrane (3 layers, fused amnion, two chorions)

Question 8

Monozygotic?

Answer 8

• Fertilization of single ovum
• Depending on time of division
  1. Dichorionic diamniotic - 25-30%
  2. Monochorionic diamniotic - 70-75%
  3. Monochorionic monoamniotic (1-2%)
  4. Conjoined twins - Very rare

Question 9

Zygosity?

Answer 9

refers to the genetic make up of the fetuses

Question 10

Chorionicity?

Answer 10

• Number of placentae
• Mechanism of twinning
• Timing of division in MZ twinning

Question 11

Explain the timing of zygote division and its effect on amnionicity and chorionicity?

Answer 11

1. days 1-3 > dichorionic/diamniotic
2. days 4-8 > monochorionic/diamniotic
3. days 8-13 > monochorionic/monoamniotic
4. days 13-15 > conjoined twins

Question 12

Diagnosis of multiple gestations?

Answer 12

Early USS
- Determine chorionicity
- Major determinant of pregnancy outcome
- Easiest and most reliable when scan done during first trimester
- 6-10weeks number of GS
- 11-14weeks lambda sign/twin peak sign

Question 13

What becomes difficult to determine on USS after the first trimester?

Answer 13

After first trimester difficult
1. Sex of fetuses
2. Number of placentae
3. Dividing membranes difficult to see as it gets thinner with increasing gestation

Question 14

Lambda sign in USS?

Answer 14

An ultrasonographic finding seen in dichorionic diamniotic twin pregnancy
- The junction of the chorion and the placenta appears triangular and resemble the Greek symbol λ (lambda)

Question 15

T sign in USS?

Answer 15

An ultrasonographic finding seen in monochorionic diamniotic twin pregnancies.
- The absence of a chorion between the layers of intertwin membrane results in the appearance of the letter T.

Question 16

Determination of zygosity?

Answer 16

1. Monochorionic = Monozygotic
2. Dichorionic : different gender = dizygotic
   - All else require genetic testing

Question 17

Maternal risk of multiple pregnancy?

Answer 17

1. Hyperemesis
2. Abortion
3. Anaemia
4. Abruption
5. Hypertensive disorders of pregnancy
6. Thromboembiolism
7. PPH
   NB: due to exaggerated maternal physiological adaptation

Question 18

Fetal risk of multiple pregnancy?

Answer 18

Growth restriction
Growth discordance
Preterm birth
Cerebral palsy
Fetal anomalies (all organ systems, more in MZ twins)
Vanishing twin
IUFD of one twin
TTTS
Twin anaemia-polycythaemia sequence(TAPS)
Twin reversed arterial perfusion sequence (TRAP)
Cord entanglement
Perinatal mortality

Question 19

Discordant fetal growth?

Answer 19

20% difference in the fetal weights of the smaller and larger twin

Question 20

Discordant fetal growth is calculated by?

Answer 20

difference in weight/weight of the larger twin x 100

Question 21

Discordant fetal growth is associated with?

Answer 21

1. intrauterine growth restriction
2. stillbirth
3. preterm birth
4. fetal abnormality
5. admission to NICU
6. respiratory distress

Question 22

Fetal growth restriction in multiple pregnancy?

Answer 22

• Can be discordant or concordant
• Antenataly, aim to predict the severity of impaired fetal oxygenation and selecting appropriate time for delivery
• DCDA twins risk 25% of SGA
• MC twins risk of IUGR 50%

Question 23

Management of fetal growth restriction?

Answer 23

• Balance the risk of iatrogenic preterm delivery for a single growth restricted fetus.
• Generally, avoid delivery before 28-30weeks (works well with DC twins)
• For MC twins, sIUFD may lead to death or severe handicap of the co-twin
• Prefer delivery before IUFD of growth restricted twin

Question 24

What is twin-to-twin transfusion syndrome?

Answer 24

A condition that occurs in monochorionic twins when one twin (donor) continuously transfers blood to the other (recipient)

Question 25

Consequences of TTTS?

Answer 25

1. dehydration 2. anemia 3. growth restriction 4. oligohydramnios in the donor and polycythemia 5. polyhydramnios in the recipient. Note: Mortality is significantly increased for both twins.

Question 26

TTTS is most common in which type of twins?

Answer 26

Unique to MC twins 1. 10% MCDA 2. 5% MCMA

Question 27

Types of vascular anastomoses in TTTS?

Answer 27

1. AV 2. AA 3. VA 4. VV - Unbalanced AV connections in one direction result in TTTS - AA anastomoses are protective

Question 28

Criteria for diagnosis of TTTS?

Answer 28

1. Single placenta mass 2. Same gender 3. Oligohydramnios in one twin and polyhydramnios in the other 4. Discordant bladder appearences 5. Haemodynamic and cardiac compromise

Question 29

Quentero severity grading for TTTS?

Answer 29

Stage1: - oligohydramnios and polyhydramnios sequence - Bladder of donor twin visible - Dopplers normal in both twins Stage 2 - oligohydramnios and polyhydramnios sequence - Bladder of donor twin not visible - Dopplers normal in both twins Stage 3 - oligohydramnios and polyhydramnios sequence - Bladder of donor twin not visible - Abnormal dopplers - AEDF/REDF in UAD Stage 4: - Signs of hydrops in one or both fetuses Stage 5: - Death of one or both fetuses

Question 30

Treatment of TTTS?

Answer 30

1. Expectant 2. Amnioreduction 3. Septostomy 4. Selective feticide 5. Laser ablation of anastomoses (definitive Rx for TTTS stage 2 and above) 6. Preterm delivery (above 28weeks)

Question 31

Antenatal care of multiple pregnancies?

Answer 31

Early booking Early scan to determine chorionicity Accurate gestation estimation Screen for down syndrome Anomaly scan at 18-22weeks if anomaly detected refer tertiary level Growth Assessment (USS) EFW from 20weeks onwards Maximum 4 weekly Growth discrepancy >25% clinically significant, refer tertiary level

Question 32

Frequency of ANC visits in multiple pregnancies?

Answer 32

Same as for singleton in first trimester More frequent after 20weeks 1. DC twins - 4 weekly until 28 weeks - 2 weekly 28-36weeks - Weekly 36-38 weeks 2. MC twins - 4 weekly until 28weeks

Question 33

ANC for MC twins?

Answer 33

MC twins (esp MCMA) Refer to Central Hospital Steroids at 28weeks Inpatient care with daily CTG from 28weeks till delivery Plan delivery at 32-34 weeks

Question 34

Nutrition in multiple pregnancy?

Answer 34

1. Ensure iron supplementation 2. Encourage normal balanced diet

Question 35

Types of Delivery of twins?

Answer 35

1. MC twins: Caesarean delivery 2. DC twins vaginal delivery unless contraindicated

Question 36

Intrapartum management of multiple pregnancy?

Answer 36

Not for Health centre Strict use of partograph Continuous fetal heart monitoring (CTG, Moyo) 2 neonatal resuscitation trolleys ready Analgesia Prepare for PPH IV access Catheterise Oxytocin infusion for prophylaxis Low threshold for CS

Question 37

Indications for c/s in multiple pregnancy?

Answer 37

1. Non Cephalic presentation of leading twin 2. Complications: preeclampsia, IUGR, oligohydramnios

Question 38

Delivery of secon twin?

Answer 38

1. After delivery of leading twin, immediately assess the lie and presentation of second twin 2. If transverse lie of twin 2, Internal podalic version then breech extraction (preferably done in OT) 3. Start oxytocin augmentation if delivery delayed > 30minutes and cephalic presentation

Question 39

Third stage management of multiple pregnancies?

Answer 39

1. AMSTL 2. Oxytocin infusion (20IU/L NS or RL) at 30dpm

Question 40

Describe management of higher order multiples?

Answer 40

e.g. Triplets 1. Care at tertiary level 2. Delivery latest 36weeks if no complication 3. Caesarean delivery by experienced operator