Multifetal Gestation and Malpresentation (Moulton) Flashcards
__1__ arise when two separate ova are fertilized by two separate sperm.
Each will have its own __2__, __2__, and __2__.
1) Dizygotic twins (Fraternal)
2) Amnion, chorion and placenta
__1__ arise from the cleavage of a single fertilized ovum at various stages during embryogenesis.
Thus the arrangement of __2__ and __2__ will depend on the time at which the embryo divides.
1) Monozygotic Twinning (Identical)
2) Fetal membranes and placentas
With Monozygotic twins, if cleavage takes place from 0-3 days, what happens with placentation? (30% of monozygotic twins have this placentation)
1) 2 chorions
2) 2 amnions
3) Placentas can be separate or fused
With Monozygotic twins, if cleavage takes place from 4-8 days, what happens with placentation? (69% of monozygotic twins have this placentation)
1) 1 chorion
2) 2 amnions
With Monozygotic twins, if cleavage takes place from 9-12 days, what happens with placentation? (1% of monozygotic twins have this placentation)
1) 1 chorion
2) 1 amnion
Monochorionic monoamniotic placentation (9-12 days) is the most dangerous because there are no separating amnions, this causes what risk to be high?
Cord entanglement is high
With Monozygotic twins, if cleavage takes place from 13-15 days, what happens with placentation?
This causes conjoined twins and if they are craniopagus (2% incidence) this means?
If they are thoracopagus (30-40% incidence)?
If they are ischiopagus (6% incidence)?
1) 1 chorion and 1 amnion
2) Joined at the cranium
3) Joined at the chest wall
4) Joined by the coccyx and sacrum
Dizygotic twins is strongly influenced by?
It is twice as common after?
1) Maternal age
2) 35 y/o
You should suspect multiple gestations if ___ is higher than normal.
hCG
When using US when determining zygosity for dizygotic twins you might see a different __1__ amongst the twins.
There may be visualization of a __2__ septum.
A __3__ sign at the base of septum may be seen.
1) Fetal gender
2) Thick amnion-chorion septum
3) Peak or inverted V
When using US when determining zygosity for monozygotic twins what may be seen?
Dividing membrane is thin
If ultrasound is not definitive in determining zygosity, what should you do?
1) Inspect placenta after delivery
2) DNA analysis
Conjoined twins results do to cleavage occurring at?
13-15 days
What presentation occurs 40-50% of the time for twins?
Vertex-vertex
__1__ and __1__ presentations can be delivered vaginally but often are delivered by cesarean section.
__2__ and __2__ twins are delivered via cesarean section.
1) Vertex-transverse and vertex-breech
2) Breech-breech and breech-vertex
Malpresentation refers to any fetal presentation other then __1__.
__2__ is the most common malpresentation.
1) Vertex
2) Breech
Breech presentation occurs when the fetal ____ or ____ presents into the maternal pelvis.
Buttocks or lower extremities
What is the most common factor associated with breech?
Prematurity
Which type of breech presentation is the most common where the thighs are flexed and the lower extremities are extended at the knees?
Which type of breech presentation is where the thighs and the lower extremities are flexed?
Which type of breech presentation is where one or both thighs are extended and one or both feet are below the buttocks?
1) Frank
2) Complete
3) Incomplete
____ involves applying pressure to the mother’s abdomen to turn the fetus in either a forward or backward somersault to achieve a vertex presentation.
External cephalic version
In order for vaginal delivery of breech presentation, the fetus must be in a ____ or ____ breech presentation.
Frank or complete
The standard of care now in most practices is to deliver all breeches by?
Cesarean section
When undergoing assisted breech vaginal delivery, a __1__ wrapped around the baby can be used for better traction.
You want to maintain cephalic flexion by applying pressure on fetal __2__, NOT fetal __3__.
__4__ is a tool that can be used in breech deliveries.
1) Towel
2) Maxilla
3) Mandible
4) Piper
__1__ presentation occurs when the presenting part of the fetus is between the facial orbits and anterior fontanelle.
The presenting diameter is the __2__ diameter.
__3__ bones are the point of designation.
1) Brow
2) Supraoccipitomental
3) Frontal
50-75% of brow presentation will convert to a face presentation through __1__ or a vertex presentation through __2__ and then deliver.
1) Extension
2) Flexion
The vertex presentation allows the ____ diameter to be the presenting diameter.
Suboccipitobregmatic
__1__ presentation is characterized by full extension of the fetal head and neck with occiput against upper back.
It can be seen frequently with fetal malformation such as __2__.
The fetal __3__ is chosen as point of designation.
1) Face
2) Anencephaly
3) Chin
The mentum must be __1__ in order to deliver a face presentation vaginally.
You can NOT deliver face presentation vaginally if the mentum is __2__. Will need to proceed with cesarean section.
1) Anterior
2) Posterior
The face presentation allows the ____ diameter to be the presenting diameter.
Trachelobregmatic
____ presentation is defined when a fetal extremity (usually the hand) is found prolapsed alongside the presenting fetal part (head).
Compound
