Twin Gestations Flashcards
Rate of twins
1: 30 births
3. 3% of all live births
If monozygotic twins cleave in first 0-4 days after fert you get
Dichorionic diamniotic twin
Di/Di
2 morula –> 2 blastocysts in own layer of trophoblast cells –> own chorion –> own amnion
If monozygotic twins cleave in 4-8 days after fert you get
monochorionic diamniotic twin
Mo/Di
*most common of the monozygotic twins (75%)
If monozygotic twins cleave in 8-12 days after fert you get
monochorionic monoamniotic twin
Mo/Mo
How many twin pregnancies are conceived spontaneously?
50%
Risk of twin pregnancies (12)
- Miscarriage
- Hyperemesis (high hCG)
- high risk of aneuploidy and anomalies
- Prenatal screening tests less sensitive and diagnostic procedures more difficult
- Maternal anemia
- Gestational diabetes ( high hPL)
- Gestational hypertension/preeclamsia
- Intrauterine growth restrictions
- Preterm birth (~36 weeks)
- Higher rate of Cesarean delivery
- Postpartum hemorrhage
- High perinatal mortality (first week)
Twin twin transfusion syndrome
- what is it?
- What does the recipient twin do?
- What does the Donor twin do?
20% of mo-di twins have unbalanced flow through connected vessels
- Recipient twin (larger)
- increases urine production to reduce blood volume - Donor twin (smaller)
- Reduces urine production to retain blood volume
When do you have to treat TTTS by?
Prior to 24 weeks or else mortality of one or both twins in 80-90% of cases
WHAT causes death of donor twin
decreased blood vol –> lower Urinary output to maintain blood vol –> oligohydramnios –> shunt away nutrients and cant support fetal growth
What causes death of recip twin
getting too much bv –> huge strain on babys heart (HF) –> too much urine prod –> polyhydramnios –> uterine distention and early deliver
- sometimes fetal hydrops
Twin peak/ Lamda sign = ?
Thick dividing membrane = DI Di
- 0-4 days
T sign ?
MO/DI
- 4-8 days
TTTS, which twin is smaller, which is larger?
Recipient twin is larger
DOnor twin is smaller
TTTS most common in which twins?
Mo-Di
