Twinning Softchalk Flashcards
When is ISCI most applicable?
Male factor infertility
removal of zona pellucida
Egg donation most applicable?
Infertility associated with ovarian failure or diminished ovarian reserve. Maternally transmitted genetic diseases
Gamete Intrafallopian Transfer
Egg and sperm deposited directly in oviduct.
Zygote Intrafallopian Transfer
Fallopian tube transfer of embryo
Embryo Cyropreservation
Early embryos resulting from IVF are preserved, transfer of four to eight cell embryos and blastocytes
Oocyte Cyropreservation
Unfertilized eggs, challenging
In Vitro Maturation
Immature oocytes and allowing completion of meiosis in vitro.
Pre-implantation genetic diagnosis
3-5 days after in vitro fertilization
NO LATER THAN 8 CELL STAGE
analyzing for genetic disorder and sex
male embryo would be at risk for X linked disorder
Risks of ART
multifetal gestation
prematurity or fetal growth restriction
rates of major congenital defects
placenta previa
No differences between ART and natural conception
psychomotor development of preschool children
socio-emotional development
Numbers for Twinning
1 in every 85 pregnancies triplets 1 in 89x89 quadruplets 1 in 89x89x89 quintuplets 1 in 89x89x89x89 HILLIN'S LAW
IVF pregnancies and twinning
37%
Monozygotic Twins
single original embryo
0.4%
identical gene makeup
Splitting at less than 8 cells (0-3 days)
Dichorionic, diamniotic
behave like dizyotic twins
two cell stage to morula stage
two identical blastocysts
Morula stage (4-8 days)
single chorion and placenta, but seperate amnions, single placenta
monochorionic, diamniotic
potential for anastomosis between twins (one receiving most of nutrition)
after blastocyst with inner cell mass (8-12)
common chorion and single amnion
monochorionic, monoamniotic
division of inner cell mass (embryonic disc)
complete division
risk for umbilical cords entanglement after 20 weeks, blood supply interupted
Splitting of bilaminar embryonic dic (after 12 days)
conjoined twins. same amnion
Dizygotic Twins
fraternal seperate oocytes produced during same mentstrual cycle most frequent increases with maternal age genetic basis three fetal membranes all seperate
Rate of dizygotic twinnings
3x more in general population
more prominent in African populations
Blastocyst implantation of dizygotic twins
Close together (placenta fusion) or far apart
Anastomoses of vessels supplying two placentae complications
In utero death of one twin
twin-twin transfusion syndrom
twin-reversed arterial profusion (TRAP, less common)
cord entanglement (not related to anastomosis)
In utero death
blood pressure of twin drops significantly, remaining twin at risk (heart failure to fill both circulator systems at once)
other twin may be killed by an embolism
TTTS
twin to twin transfusion syndrom
monchorionic, diamniotic twins (10-20%)
unbalanced blood flow between twins
Donor twin of TTTS
oligohydramnios
growth restriction
renal insufficiency
Recipient twin
polyhydraminios
cardiac enlargement
eventually cardiac failure
TRAP sequence
1 in 35,000 births
pump twin provides all the blood flow to acardiac/acephalic twin through anastomoses
Pump twin risks
cardiac failure, 50-75% death, provides all blood flow to acardiac/acephalic twin
Acardiac/acephalic twin
unable to survive without pump twin in TRAP
dies when pump twin dies
Cord entaglement
monochorionic, monoanmnionic twin
most common complication
death of one or both twins if it interrups blood supply through umbilical cord
Triplet variation
one zygote–identical
two zygotes-identical twins and singleton
three zygotes–different sexes or same sexes (no more similar than infants from three separate pregnancies)
What type of oocytes are retrieved during IVF? When are they transferred into the mother?
Superovulation. Mature oocytes. Transvaginal retrieval. Fertilization in vetro. blastocyst stage. transcervical transfer into endometrial cavity.
