Multifetal Gestation (Moulton) Flashcards
Multiple gestation
any pregnancy in which two or more embryos or fetuses occupy the uterus simultaneously
Dizygotic twins (fraternal)
two separate ova are fertilized by two separate sperm; each will have its own amnion, chorion and placenta
Monozygotic twins 0-3 days of cleavage
dichorionic, diamniotic
Monozygotic twins 4-8 days of cleavage
monochorionic, diamniotic
Monozygotic twins 9-12 days of cleavage
monochorionic, monoamniotic; most dangerous since there are not separating amnions; high risk for cord entanglement and net mortality
Monozygotic twins >13 days of cleavage
conjoined twins
Craniopagus
conjoined twins joined at the cranium (2%)
Thoracopagus
conjoined twins joined at the chest wall (30-40%) most common
Ischiopagus
conjoined twins joined at the coccyx and sacrum (6%)
What is the most important step after diagnosing twins
determination of zygosity
Dizygotic twins on US
different genders; visualization of thick amnion-chorion septum; “peak” or “inverted V” sign at the base of the septum
Most common inter-placental vascular anastomoses in conjoined twins
arterial-arterial
Twin Twin Transfusion Syndrome (TTTS)
uncompensated arterial-venous anastomoses; blood flow going from one twin to the other;
donor twin - hypovolemia
recipient twin - hypervolemia
**both twins are at risk for demise from heart failure; poor prognosis
Treatment of Twin Twin Transfusion Syndrome (TTTS)
laser photocoagulation
Acardiac twin
fully formed lower extremities; no anatomic structures cephalad of the abdomen
Retained dead fetus syndrome
single fetal death in utero; if gestation < 12 weeks, the dead fetus is reabsorbed “vanishing twin syndrome”; >12 weeks, twin shrinks and is called fetus papyraceus
fetus papyraceus
single fetal death in utero; >12 weeks gestation, twin shrinks and is called fetus papyraceus
When should monoamniotic twins be delivered?
32 weeks
Vertex-transverse & vertex-breech presentation
often delivered C-section
Breech-breech & breech-vertex
always delivered C-section
Average delivery for triplets
33 weeks; C-section
Average delivery for quadruplets
29 weeks; C-section
What is the most common malpresentation in twins
breech; most common factor is prematurity
Which forceps are used when a baby is in a breeched position?
Piper forceps
Brow presentation
presenting fetus is between the facial orbits and anterior fontanelle; frontal bones are the point of designation
Face presentation
full extension of the fetal head and neck with occiput against the upper back
Compound presentation
fetal extremity is found prolapsed alongside the fetal head (like raising their hand)
External Cephalic Version (ECV)
applying pressure to the mother’s abdomen to turn the fetus in either a forward or backward somersault; indicated 36 weeks gestation, not in labor; contraindicated in placenta previa
