Multiple gestations/complications registry review Flashcards
Complications associated with multiple gestations
-Increased risk of preeclampsia
-Preterm delivery
-Low birth weight
-Fetal anomalies
-Miscarriage
-Perinatal death
Twinning
Either arise from 2 separate eggs that were fertilized or 1 zygote that splits
Median gestational age for delivery of twins
36 weeks
Multiple gestations greater than twins are most likely the result of assisted reproduction and have increased risk of complications
Dizygotic
2 separate eggs are fertilized
-Fraternal since they come from separate ovum
-Dichorionic/diamniotic ALWAYS
-2 GS, 2 placenta, 2YS, 2 amnion
*MOST common
Monozygotic
1 ovum that splits
-Identical
*EARLIER split = more divided they will be
-Dichorionic/diamniotic (<4days)
-Monochorionic/diamniotic (4-8days)
-Monochorionic/monoamniotic (>8days)
Chorionicity
Chorion forms the gestational sac and placenta
Dichorionic
Two of each, gestational sac and placenta
Monochorionic
One gestational sac and placenta
Amnionicity
Amnion is the inner membrane and goes with yolk sac
Diamniotic
A membrane between and 2 yolk sacs
Monoamniotic
One membrane and one yolk sac
Dichorionic/diamniotic
-Early division (<4days)
-2GS, 2 placenta, 2 amnion, 2YS
Monochorionic/diamniotic
-4-8days
-1GS, 1 chorion, 1 placenta, 2 amnions, 2 YS
-Thin membrane inserting like a [T] into placenta which means one shared placenta
*MOST common division
Monochorionic/monoamniotic
-Late division (>8days)
-Everything shared
-1GS, 1 chorion, 1 placenta, 1 amnion, 1 YS
1st trimester determination of twin type
-Dichorionic seen as two completely separate GS within uterine cavity (must also be diamniotic)
-Monochorionic appears as 1 GS, count the amnions or YS to determine amnionicity
2nd trimester determination of twin type
-Dichorionic is more obvious if 2 separate placentas are identified
*Look for twin peak sign (2 placentas may appear as 1 fused placenta)
Twin complications (monochorionic twins ONLY)
Monochorionic share one placenta therefore increased risk of fetal shunting and growth issues
Twin to twin transfusion syndrome (TTTS)
Fetal shunting through vessels in the placenta, donor to recipient
Donor twin in TTTS
Gives blood to other, eventually suffers from IUGR
-IUGR
-Oligohydramnios
-Anemia
Recipient twin with TTTS
Receives too much blood and can suffer from hydrops and CHF due to the overload of blood going to the heart
-Larger
-Polyhydramnios
-Hydrops/CHF
1st initial sonographic indication of TTTS
Discordant fetal growth
Stuck twin
Most severe TTTS. Oligohydramnios is so severe that the donor twin appears to be stuck to the side of the uterine wall
-Determine donor by size or sac difference
Twin reversed arterial perfusion
(TRAP)
Abnormal anastomoses of placental vessels that support the growth of parasitic or acardiac twin
-1 normal fetus, 1 abnormally developed with NO heart
Pump twin
Living twin in TRAP twins, maintains the growth of the parasitic twin
-Mortality rate 50% secondary to polyhydramnios and prematurity
Acardiac twin
Abnormally developed twin in TRAP twins, no heart
-Absent upper body
-Absent heart
-Hydrops
Conjoined twins
Occurs in ONLY monochorionic/monoamniotic twins when zygote splits > 13 days
-Multiple forms
-40% chance stillborn
Thoracopagus conjoined twins
Twins fused at the chest
*MOST common
Omphalopagus conjoined twins
Twins fused at the chest
Twin demise
When one or more embryos or twins die in utero
*Dichorionic twins have a greater chance of survival in case of twin demise (especially early 1st trimester)
Fetus papyraceus
Fetal death in 1st trimester and is maintained, not resorbed. May eventually become vanishing
Vanishing twin
Death of a twin in the early 1st trimester and is reabsorbed
Monochorionic fetal demise
One demise will often lead to the demise of the other
Twin embolization syndrome
Demised twin begins to breakdown and vascular products can travel through common vascular channels with shared placenta
-CNS and kidneys are usually affected
-Possible with monochorionic fetal demise in 2nd trimester
