Ch. 31 Multiple Gestations Flashcards
shunting of venous or arterial blood from one twin to another through placental circulation
twin–twin transfusion syndrome (TTTS)
asymmetric fetal weight between twins
discordant growth
an abnormal accumulation of fluid in at least two fetal body cavities
hydrops
type of amniocentesis used to remove a large amount of amniotic fluid around a fetus suffering from polyhydramnios
therapeutic amniocentesis
a treatment that uses lasers to separate abnormal placental vascular connections between twins that are suffering from twin–twin transfusion syndrome
endoscopic-guided laser photocoagulation
when a twin fetus, suffering from twin–twin transfusion syndrome, experiences severe oligohydramnios and is closely adhered to the uterine wall
Stuck twin
Sonographic Findings of ___________
1.Monochorionic twinning
2.Discordant fetal growth
3.Oligohydramnios around donor twin
4.Polyhydramnios around recipient twin
5.Recipient may be hydropic
Twin–Twin Transfusion Syndrome
With TTTS, the twin that shunts blood to the other is called the “_______” twin and is often _________than the twin receiving extra blood, the “_______” twin.Treatment options include therapeutic amniocentesis and endoscopic-guided laser photocoagulation of the communicating placental vessels.
donor; smaller; recipient
A complication that carries a high mortality rate for __________twins is twin–twin transfusion syndrome (TTTS)
monochorionic
With TTS, the donor twin often suffers from ________ and ________, whereas the recipient experiences _______ and __________
anemia and growth restriction; hydrops and congestive heart failure
discordant growth, which is described as a _____ to ______ ________ in the estimated fetal weight of the smaller fetus compared to the larger.
15% to 25% reduction
vascular connections
anastomoses
an abnormally developed twin that has an absent upper body and no heart
acardiac twin
________ refers to severe oligohydramnios surrounding a twin that appears to be closely associated with the uterine wall
*seen with TTTS
Stuck twin
Abnormal anastomoses of placental vessels may result in a parasitic twin or _______. This is considered to be a severe form of TTTS.
acardiac twin
Acardiac twinning may also be referred to as ____________ sequence or acardiac parabiotic twinning.
twin-reversed arterial perfusion (TRAP)
another name for acardiac twinning
twin-reversed arterial perfusion (TRAP)
Sonographic Findings of ________
1.Normal pump twin
2.Acardiac twin—absent upper body, absent heart, and hydrops
Acardiac Twin
With acardiac twinning, there is one normal fetus, the “_________,” and an abnormally developed fetus containing no________. The normal fetus maintains the growth of the parasitic twin. Abnormally developed fetus also has absent upper body, and hydrops
pump twin; no heart
The pump twin has a perinatal mortality of 50% to 55%, secondary to _________ and ________.
polyhydramnios and prematurity
Conjoined twins can result from ____________twinning.
monochorionic monoamniotic
conjoined twins attached at the chest
thoracopagus
conjoined twins attached at the abdomen
omphalopagus
The most common forms of conjoined twinning are _______ and _________, which is the attachment at the chest and abdomen, respectively.
thoracopagus;omphalopagus
twins joined at the cranium
craniopagus
conjoined twins joined back-to-back in the sacral region
pyopagus
dead at birth
stillborn
Conjoined twins may also be joined at the cranium (___________) or back-to-back in the sacral region, which is termed __________.
(craniopagus); pyopagus
The prognosis is poor for conjoined twins. They have a 40% chance for being _________, with many dying within the first 24 hours.
stillborn
The death of a twin, and subsequent reabsorption of the embryo during the first trimester, is termed a __________
vanishing twin
the death and reabsorption of a twin
vanishing twin
the death of one fetus in a twin pregnancy that is maintained throughout the pregnancy; actually means paperlike fetus
fetus papyraceus
If the fetus dies in the first trimester and is maintained throughout the pregnancy, it is referred to as ______________. With dichorionic twins, the surviving twin is rarely affected by the death of the other. However, the death of a _________ twin during the first trimester frequently leads to the death of the other twin.
fetus papyraceus; monochorionic
The death of a ________ twin during the second or third trimester can lead to life-threatening problems in the surviving twin. Potential troubles exist as a consequence of the breakdown of the demised twin.
monochorionic
Vascular products, as a result of the breakdown of tissues, travel from the demised twin to the surviving twin by means of the common vascular channels within the shared placenta, a complication known as __________
twin embolization syndrome
Twin embolization syndrome can result from the death of a __________ twin.
monochorionic
when vascular products travel from a demised twin to the surviving twin by means of the common vascular channels within the shared placenta
twin embolization syndrome
the development of a cystic cavity within the cerebrum; may be the result of an intraparenchymal hemorrhage
porencephaly
In the death of a monochorionic twin, particularly the __________ and the __________ are affected in the surviving twin, with a documented 25% risk of death or neurologic damage for the survivor. Intracranial abnormalities such as hydrocephalus and porencephaly are common in the survivor as well
central nervous system and kidnyes
Triplet pregnancies can manifest with different combinations of ________ and ________. For example, triplets can be trichorionic triamniotic and dichorionic triamniotic. Most triplet and quadruplet pregnancies result from the use of ovulation induction or in vitro fertilization
chorionicity and amnionicity;
Unfortunately, multiple gestations beyond twins have an increased likelihood of discordant growth, miscarriage, and perinatal death. When assisted reproduction is used, resulting in a high number of multifetal pregnancies, multifetal __________ may be used. With sonographic guidance, a needle punctures the fetal heart and potassium chloride is injected.
reduction
pregnancy-induced maternal high blood pressure and excess protein in the urine after 20 weeks’ gestation
preeclampsia
the condition of having a deficient number of red blood cells
anemia
underdevelopment of the lungs
pulmonary hypoplasia
a shortage of oxygen or decreased oxygen in the blood
hypoxia
Mothers expecting multiple gestations have an increased risk of developing _________ and ________. The risk for _______ delivery is increased 7 to 10 times more compared to a singleton pregnancy, with an associated ______ birth weight. The median gestational age of delivery for twins is 35 weeks, and for triplets and beyond, the gestational age of delivery is even earlier.
preeclampsia and anemia; preterm; low; 35 weeks
Infants born with low birth weight, and specifically before 32 weeks’ gestation, often suffer from _____________ with episodes of ________. _______ at the time of birth can cause tiny, fragile blood vessels within the immature brain to rupture, leading to intracranial hemorrhage and possible irreversible neurologic complications or death.
pulmonary hypoplasia; hypoxia; Hypoxia
Terminology associated with conjoined twins
Conjoined Terminology: __________
Area of Union:
Joined at the head
Craniopagus
Terminology associated with conjoined twins
Conjoined Terminology: __________
Area of Union:
Joined at the thorax (chest)
Thoracopagus
Terminology associated with conjoined twins
Conjoined Terminology: __________
Area of Union:
Joined at the abdomen
Omphalopagus
Terminology associated with conjoined twins
Conjoined Terminology: __________
Area of Union:
Joined at the pelvis (spine connected at a 180 degree angle, facing away from one another)
Ischiopagus
Terminology associated with conjoined twins
Conjoined Terminology: __________
Area of Union:
Joined at the sacral region or back-to-back
Pyopagus
With a ______________pregnancy, the membrane will be thin and seen separating at the junction point with the placenta, a sonographic sign referred to as the “T sign.”
monochorionic diamniotic
If separate placentas are noted, then the pregnancy must be ___________. In addition, noting a triangular extension of the placenta at the base of the dividing membrane is indicative of a _____________pregnancy. This is referred to as the twin peak sign, lambda sign, or delta sign
dichorionic diamniotic
a triangular extension of the placenta at the base of the membrane and is indicative of a dichorionic diamniotic pregnancy; also referred to as the delta sign or twin peak sign
lambda sign, twin peak sign, delta sign
If the twins are _______ sexes, then one can assume that the twins are dichorionic. Same-sex fetuses that have a single placenta and a thin membrane separating them are almost certainly __________
different; monochorionic
The presence of _____ yolk sac and two fetuses is indicative of a monoamniotic gestation, whereas the presence of ______ yolk sacs is indicative of a diamniotic gestation.
one; two
During the first trimester, ________ twins will have a thick membrane separating the two amniotic sacs, whereas __________twins will have a thin membrane or no membrane at all between them
dichorionic; monochorionic
Monozygotic twins arise from a _______ zygote that splits. Thus, monozygotic twins are always _________ twins because they share their design from only one fertilized egg. It depends on the time at which this division, or ________, takes place as to how many placentas and amnions may be present with monozygotic twins
single; identical; cleavage
twins that result from the split of a single zygote and share the same genetic structure
identical twins
the division of a cell
cleavage
What are the 3 types of monozygotic twins?
(i) monochorionic diamniotic, (ii) dichorionic diamniotic, and (iii) monochorionic monoamniotic
_______________twins are the most common form of monozygotic twins.
Monochorionic diamniotic
It is important to note that when two fetuses share the _______placenta, complications are more likely to occur.
same
The least probable monozygotic twinning to occur is _________________twins. A late split, beyond day 8 postconception, will result in _______________twins. Because of the shared amniotic sac and this delayed division, monochorionic monoamniotic carries the additional risk of ______________.
monochorionic monoamniotic; monochorionic monoamniotic; conjoined twins
monoamniotic, monochorionic twins that are attached at the head, thorax, abdomen, or lower body
conjoined twins
___________, the most common form of twinning, arise from two separate fertilized ova.
Dizygotic twins
Dizygotic twins are referred to as ________ twins because they have their own genetic structure and can differ from each other in many ways.
fraternal
Dizygotic twinning always results in ___________ twins. That means, if there are _____ placentas, there must be ______ amnions. However, in early gestation, the placentas may fuse and appear as one large placenta with sonography.
dichorionic diamniotic; two; two
twins that result from the fertilization of two separate ova and have dissimilar characteristics
fraternal twins
an unfertilized egg
ovum
the cell formed by the union of two gametes; the first stage of a fertilized ovum
zygote
relates to the number of zygotes (fertilized ova)
zygosity
_________ twins arise from a single zygote, whereas ________ twins form from two separate zygotes.
Monozygotic; dizygotic
coming from one fertilized ovum or zygote
monozygotic
two ova are fertilized by two sperms
dizygotic
The fertilization of a single ovum that eventually divides, or the fertilization of several ova, can produce _______gestations. A fertilized egg is referred to as a ______. In multiple gestations, the term _________ refers to the number of eggs that are fertilized.
multiple; zygote; zygosity
the outer membrane of a gestation that surrounds the amnion and developing embryo
chorion
the inner sac that contains the embryo and amniotic fluid; echogenic curvilinear structure that may be seen during the first trimester within the gestational sac
amnion
Chorionicity, often referred to as placentation, relates to how many ________ are present.
placentas
relates to the number of chorions and the type of placentation in a multiple gestation
Chorionicity
________ refers to how many amnions or amniotic sacs are present. Twins who share the same amniotic sac are referred to as _______, whereas twins who have their own individual amniotic sac are _________.
Amnionicity; monoamniotic; diamniotic
Patients with multiple gestations may present with the clinical indication of_________ and also an _______human chorionic gonadotropin blood level compared to a singleton pregnancy.
large for dates; elevated
When compared with singleton pregnancies, twins have a four times higher risk of fetal _____ and a six times higher neonatal ____ rate.
mortality; morbidity
the rate of actual deaths
mortality
the relative frequency of occurrence of a disease; condition of suffering from that disease
morbidity
A maternal ____of multiple gestations, assisted reproductive therapy (ART), ovulation _____ drugs, _____ maternal age, and maternal _____ have all been shown to increase the probability of multiple gestations
history; induction; advanced; obesity
techniques used to treat infertility
assisted reproductive therapy (ART)
a maternal age of 35 years or older
advanced maternal age
coexisting ectopic and intrauterine pregnancies
heterotopic pregnancies.
It has been reported that as many as 43% of triplets and higher order pregnancies are linked with _____. Thus, patients with a history of ovulation induction drugs or ART should be evaluated systematically, because they are more likely to have not only multiple gestations but also __________.
ART;heterotopic pregnancies
Zygosity:
________
Description:
Two separate fertilized ova
Result:
Dichorionic diamniotic
Appearance:
__________
Dizygotic; fraternal
Zygosity:
Monozygotic
Description:
One zygote splits between 4 and 8 d
Result:
_________
Appearance:
Identical
Monochorionic diamniotic
Zygosity:
Monozygotic
Description:
One zygote splits before day 4
Result:
_________
Appearance:
Identical
Dichorionic diamniotic
Zygosity:
Monozygotic
Description:
One zygote splits late
Result:
_________
Appearance:
Identical
Monochorionic monoamniotic
All of the following complications are associated with multiple gestations except:
a. preterm delivery
b. high birth weight
c. maternal anemia
d. maternal preeclampsia
b. high birth weight
The demise of a twin can lead to the development of neurologic complications in the living twin as a result of:
a. twin embolization syndrome
b. TTTS
c. TRAP syndrome
d. dichorionicity
a. twin embolization syndrome
Twins having two placentas and one amniotic sac are referred to as:
a. monochorionic diamniotic
b. monoamniotic dichorionic
d. dichorionic monoamniotic
d. This does not occur
d. This does not occur
