Embryos - Assisted Reproduction Flashcards
1st 6 days of embryonic development
penetration of sperm into ZP
1st division by mitosis
2 cell stage
4 cell stage
morula
Process of implantation
IUI
intrauterine insemination
ICSI
intracytoplasmic sperm injection
GIFT
gamete intrafallopian transfer
ZIFT
zygote intrafallopian transfer
PESA
percutaneous epididymal sperm aspiration
ET
embryo transfer
TESE
testicular sperm extraction
SUZI
subzonal sperm injection
PGD
preimplantation genetic diagnosis
most common types of assisted conception
IUI
IVF
ICSI
required procedures for assisted reproduction
superovulation - hormonal manipulation to enhance ovulation and release multiple oocytes during ovulatory cycle
sperm preparation
assisted fertilisation
how is superovulation carried out
human menopausal gonadotrophin - taken from urine of postmenopausal women - follicle stimulating hormone (FSH) and leutinising hormone (LH) activity
Recombinant FSH
recombinant LH
sperm preparation procedure
select PMNS (progressively motile normal sperm)
remove seminal plasma, WBCs and bacteria
sperm capacitation - coating of sperm with seminal plasma proteins to allow sperm to become fertile - in vivo or in test tube
intrauterine insemination procedure
sperm vol
success rate
sperm sample deposited in uterus just before release of an oocyte in a natural or stimulated cycle
soft catheter
give hCG at injection or up to 24 hours later
sperm vol = 0.2-0.3ml
pregnancy rates = 15% per cycle
gamete intrafallopian transfer procedure
Laparoscopic technique in which oocyte and sperm placed in fallopian tube - allowing in vivo fertilisation
superovulation
US guided transvaginal oocyte retrieval
0.1-0.2ml sperm with 2-3 oocytes
in vitro fertilisation procedure
taking oocyte from woman
fertilising them in the lab with her partner’s sperm
transferring resulting embryos back to her uterus 3 or 5 days later
superovulation → insemination → embryo transfer → luteal support
superovulation with IVF - how does it occur
gonadotrophin stimulation
monitoring follicular development
US guided transvaginal oocyte retrieval
occyte fertilisation with sperm
containers used with IVF insemination
what is each oocyte inseminated with
how is fertilisation later detected
test tubes, petri dishes, multi-well dishes
each oocyte inseminated with 0.5-1 ml PMNS (progressively motile normal sperm)
fertilisation detected 12-20 hours later by presence of:
- 2 pronuclei in oocyte cytoplasm
- 2 polar bodies in perivitelline space
Syngamy
combination of maternal and paternal pronuclei 24 hours after insemination
further cleavage occurs at 24 hour intervals
ZP and polar bodies
progress from 2 cell stage to blastocyst
with IVF, when does embryo transfer take place
embryos transferred to uterus on 2nd or 3rd day after IVF
4-8 cell embryos
2-3 embryos transferred in 20 ul of culture fluid
transabdominal US (ultrasound) to see fluid placed in uterus
cryopreserve excess embryos
luteal support with IVF
progesterone (P4) necessary for pregnancy maintenance
premature luteolysis in some superovulatory regimens
P4 supplementation until menses occur or woman has +ve pregnancy test
ICSI - intracytoplasmic sperm injection
procedure
injection of single sperm into single oocyte in order to achieve fertilisation
Superovulation → US guided transvaginal oocyte retrieval → IVF
oocytes injected with sperm using special microscopes, needles and micromanipulation equipment
indications of ICSI
- low sperm conc, motility, abnormal morphology
- antisperm antibodies
- fertilisation failure after conventional IVF
- ejaculatory disorders
- absence of vas deferens or obstruction of ejaculatory ducts
assisted hatching indications
couples having IVF with
- female partner > 37
- poor quality embryos - excessive fragmentation, slow rates of cell division
assisted hatching procedure
embryo held with a specialised holding pipette
a needle used to expel an acidic solution against ZP
small hole made in ZP
embryo washed and put back in culture in incubator
ET shortly after hatching procedure
further advances and uses of assisted conception technology
cryopreservation of sperm, embryo, oocyte, ovarian tissue
growth of human follicles and oocytes in vitro
in vitro maturation and transplantation of human spermatozoa
definition of infertility
inability to conceive after 1 year of unprotected and regular sexual intercourse
primary infertility
couples have never had children
secondary infertility
couples initiated conception in the past and are only now having difficulty
proportion of partner affected by infertility
female partner - 35%
male partner - 35%
both partners - 20%
unknown cause - 10%
infertility more common with increasing age
Highest to lowest - most common causes of female infertility
disorders of ovulation
fallopian tube disorders
pelvic adhesions
endometriosis
hyperprolactinemia
male infertility causes
abnormal semen parameters - count, motility, morphology
main techniques for assisted reproductive technology
IUI
IVF - embryo transfer
ICSI
Assisted hatching
Preimplantation Genetic Diagnosis (PGD)
identify genetic conditions in embryo before ET (embryo transfer)
Haemophilia
CF
Aneuploidy
when is PGD performed
with IVF
8 cell stage (3 days old) embryo biopsy
obtain 1-2 blastomeres for genetic testing
3 day old embryos
how is PGD analysis performed (preimplantation genetic diagnosis)
multicolour fluorescence in situ hybridisation (FISH)
polymerase chain rxn (PCR)
Interphase nucleus
chromosomal abnormalities
