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Flashcards in Twin Pregnancy Deck (26):

These are twins divided from the division of one fertilized ovum or zygote. By definition, they are identical, always the same gender

Monozygotic twin


These are twins which are derived from two completely separate ova, each fertilized by a different sperm. In essence, these are simply brother or sisters that shear the same uterus at the same time, never identical, fraternal twins

Dizygotic twins


Dizygotic twins comprises ______ or about ______% of all twins occurring in one out of 80 conceptions, lowest risk of all twins because they have their own ______ and ______

Two thirds or 66%
Placenta and amniotic sac


Dizygotic twins are more common in ______ women than Asians, tends to be inherited trait



The ______ sign is used to diagnose a dizygotic/dichorionic/diamnionic twin pregnancy in the second and third trimester, this simply means that one placenta dissects between the other placenta and amniotic sac

Twin peaks


what does the number of chorions, placentas, amnions or amnionic sac depend on in monozygotic twins?

when exactly the zygote divided


if the morula divided in the first ______ days, each fetus will have its own chorion and its own amnion (dichorionic/diamnionic) there will be two widely separated gestational sacs in the first trimester, no twin peak sign until the second and third trimesters of dichorionic/diamnionic twin pregnancies

0-3 days


if the preimplantation blastocyst divides on day ______ they will share a placenta but have two separate amnionic sacs (monochorionic/diamnionic) on TV you will see a thin dividing membrane in 1st trimester (the amnionic membrane); one placenta; no twin peak at all

4-7 days


if the blastocyst divides on days ______, monochorionic/monoamnionic will result; no dividing membrane at all; in 1st trimester the twins are close in relationship to one another**



**deciding the amnionicity and chorionicity is best done in the first trimester with ______ sonography**



if the morula divides after day ______, conjoined twins is the result



what are the conjoined twin sight of union descriptions of; omphalopagus, pyopagus, ishshiopaus, and craniopagus

omphalopagus- xiphoid to umbilicus
pyopagus- sacrum
ishshiopaus- ischium/pelvis
craniopagus- head


what are the clinical findings of twin pregnancies?

higher beta hCG levels, higher maternal serum alpha-fetoprotien levels, and bigger uterine size/large for dates


what are the maternal complications of twin pregnancy?

hypertension/preeclampsia and eclampsia, preterm labor/premature delivery, anemia, postpartum hemorrhage (because of inadequate contractions), and placenta abruption


what are the fetal complications of twin pregnancy?

prolapse or entanlement of the cord and cord knots (in monoamnionic twins) interuterine growth retardation due to placental insufficiency and difficult delivery


when there are higher levels of multiples, a patient and their physician may elect to do selective ______ in order to lower the risks to the fetuses and their mother



in terms of in vitro fertilization, why will most fertility doctors not implant more than 2 fertilized eggs?

one of those fertilized eggs may split and result in an identical pair set of twins plus the other fetus, many agree triplets are already a risk


this occurs with demise of one twin, usually because one twin had a chromosomal abnormality. You will see that one twin is bigger than the other within normal fetal heartbeat and the other is smaller and has no fetal heartbeat; no treatment for this; demised twin will resorb into the uterine wall

vanishing twin; sometimes there is small amounts of vaginal bleeding


this syndrome affects only monozygoitc twins because there is a shared placenta, it results because of anomalous development of vascular connections between the shared placenta; most serious form-vein anastomoses shunts blood away from the donor twin, to the recipient twin

twin transfusion syndrome/poli-oli sequence


in twin transfusion, how is the recipient twin affected?

polyhydramnios, hydrops-edema, pleural effusion, ascites, large for dates


in twin transfusion, how is the donor twin affected?

oligohydramnios, small for dates, "stuck" twin (in small amount of fluid and cant move)


this is the passage of thromboplastic material or blood clots from a dead monochorionic twin to the remaining live twin through the shared intraplacental vasculature; can result in neurologic, gastrointestinal, or genirourinary deficits in the live fetus

twin embolization syndrome


what are the findings for twin embolization syndrome?

interuterine death of one twin, hydrops fetalis in the live twin, polyhydramnios, intra-cranial hemorrhage, porencephaly, ventriculomegaly, enlarged echogenic kidneys in live fetus


this is a bizarre form of monozygotic, monochorionic twins in which the acardiac twin has no direct vascular connection with the placenta. arterial anastomosis shunts blood from the donor twin to the acardiac twin

twin reversed arterial perfusion (TRAP) or sequence/acardiac twinning/para biotic twin


in TRAP, the donor twin is called the ______ twin and is usually sonographically normal except for the enlarged heart or cardiomegaly; this twin could develop heart failure and hydrops due to the increased burden of being the heart for both twins



US findings in the acardiac and pump twin in TRAP is?

acardiac twin- multiple structural anomalies and no cardiac motion, still grows and moves, anencephaly or small head, limited upper extremity development, and cystic hygroma
the pump twin-hydrops fetalis