Multiple Gestations Flashcards
factors that increase the likelihood of multiple gestations
history
advanced maternal age
assisted therapy
maternal obesity
singletons vs. multiples mortality rate
twins have 4x ^ risk for fetal mortality and 6x ^ risk for neonatal morbidity rate
zygote
fertilized egg
zygosity
in multiple gestations, this term refers to the number of eggs that are fertilized
monozygotic
twins arising from a single zygote
dizygotic
twins form from 2 separate zygotes
chorion
structure that forms the placenta
chorionicity
how many placentas are present
monochorionic = twins who share a placenta
dichorionic = twins that have separate placentas
amnionicity
how many amnions or amniotic sacs are present
monoamniotic = twins who share the same sac
diamniotic = twins that have their own sac
dizygotic twinning
2 separate fertilized ova
**most common form of twinning
“FRATERNAL TWINS”
monozygotic twinning
arise from a zygote that splits
monochorionic-diamniotic twins = more common
“IDENTICAL TWINS”
at what days does the split and result in monochorionic-diamniotic
zygote splits between 4 & 8 days
split (days) that results in a dichorionic-diamniotic pregnancy
zygote splits prior to day 4
split (days) that results in a mono-mono pregnancy
zygote splits late, after 8 days
split (days) for conjoined twins
split extremely late, 8-12 days
twin peak sign
“Lambda Sign”
indicative of a di-di pregnancy
delta sign
“T-sign”
monochorionic-diamniotic pregnancy
different gender twins vs. same gender twins
dichorionic
vs.
monochorionic
vanishing twin
death and reabsorption of the embryo during the 1st trimester
if embryo is not reabsorbed = fetal papyraceus
monochorionic twins, death of one, results in the death of other
twin embolization syndrome
vascular products travel from the demised twin to the surviving twin by means of the common vascular channels with the shared placenta
what risk ^ with multiple gest. pregnancies?
preterm labor
chorion frondosum
the fetal contribution of the placenta derived from the blastocyst and contains the chorionic villi
causes of placentomegaly
diabetes maternal anemia infection fetal hydrops Rh isoimmunization multiple gestations (>4 cm thick)
causes of a thin placenta
long-standing diabetes IUGR placental insufficiency poly- preeclamsia
what is a common cause of painless vaginal bleeding in 2nd and 3rd trimester
placenta previa
when is placenta previa more likely to occur
hx of multiparity
advanced maternal age
prior c-section
vasa previa is often assoc. with what type of cord insert
velamentous
placental abruption
premature separation of the placenta from the uterine wall before the birth of the fetus
maternal causes of placental abruption
HTN preeclampsia cocaine cigarettes poor nutrition trauma
chorioangioma
most common placental tumor
^ MSAFP
most common location is adjacent to the umbilical cord insertion
assoc. with poly-, IUGR, and fetal hydrops
allantoic cyst
a mass adjacent to the cord near the fetal abd
assoc. with omphalocele and aneuploidy
hemangioma
most common tumor of the umbilical cord (but very rare)
located near the cord insert on placenta
fetal malformations assoc. with polyhydramnios
cardiac/chest anomalies chromosomal anomalies duodenal atresia esophageal atresia facial anomalies gastroschisis neural tube defects omphalocele Rh incompatibility twin to twin transfusion syndrome
what does TORCH stand for
toxoplasmosis other infections rubella cytomegalovirus herpes simplex virus
sonographic findings of TORCH
presence of intracranial calcifications
microcephaly
ventriculomegaly
hepatosplenomegaly
diethylstilbestrol
drug used to treat threatened AB & PTL in 1970s
can cause cervical incompetence
cervical cerclage
the placement of stitches in the CX to hold it closed
for incompetent CX
