W9- Lecture 50- Assisted reproduction techniques Flashcards
what is the definition for infertility
what term do we usually use instead ?
Usually defined as having a continuous period of 12 months or more without conceiving despite regular, unprotected intercourse.
sub-fertility
name the three assisted techniques for pregnancy
+ when used
Intra-uterine insemination (indicated for problems with semen deposition, low sperm count)
In vitro fertilisation (IVF) (tubule blockage; oligozoospermia/aka too few sperm )
Intra-cytoplasmic sperm injection (ICSI)(tubule blockage; severe oligozoospermia/aka too few sperm )
describe the collection of male gametes in assistive techniques
most representative sample ?
time frame
Usually by masturbation into a labelled, sterile pot provided.
Ejaculation into a spermicide-free condom during intercourse believed to result in the most representative sample.
Needs to be provided to the clinic within ½ - 2 hours of production.
how is a male sample processed for assistive techniques
where is this required
Following liquefaction,
sample is centrifuged to remove seminal plasma & pellet
washed & resuspended in buffer or medium.
e.g. for IUI or IVF, subjected to “swim up” procedure to enrich motile sperm.
what is the Swim-up purification of sperm?
Pellet suspended in 2.5 ml pre-warmed Ham’s F-10 culture medium
Centrifuged & the pellet over-laid with medium
Tube sealed, inclined at 45 and kept at 37°C for 60-90 minutes in 5% CO2.
Sterile Pasteur pipette used to remove the supernatant containing actively motile sperm
describe the collection of female gametes in assistive techniques
Usually requires induction of superovulation via FSH
Use of Gonadotropin-releasing hormone analogues: agonists to reduce exogenous gonadotrophins; antagonists to time LH surge
Ovulation stimulated with Human chorionic gonadotropin
Oocytes collected by aspiration(sucking) under ultrasound guidance
what is Ovarian Hyperstimulation Syndrome
what does this cause lead to ?
/ what increased risk ?
time frame
Potentially fatal condition resulting from excessive follicular development.
Over-production of oestrogen causes oedema in abdomen (bloating, nausea); increased risk of thrombosis.
Can persist through first couple of weeks of pregnancy.
Intra-uterine insemination (IUI)
does it need ovarian stimulation ?
risks?
indications ?
negatives (other than risks )
+ positives
May or may not require ovarian stimulation, depending on patient
If used, higher risk of multiple pregnancy (health risks to offspring)
Can lead to inappropriate use, e.g., ovulatory disorders; male-factor infertility where sperm count is not a contributory factor; etc
Numerous indications for its use
- cryopreserved gametes - donor sperm - post-operative scarring of reproductive tract - mild, male factor infertility (oligozoospermia) - erectile dysfunction
Has led to lower success rates per cycle & suggestions it should not be available on NHS.
Its appropriate use is a cheaper, less arduous option than IVF or ICSI.
In vitro fertilisation
what gametes need to be collected ?
incubation
ratio sperm to oocyte
Requires both types of gamete to be collected.
Incubation in fertilisation medium – may contain factors to stimulate sperm capacitation.
Incubate 1 oocyte per several hundred spermatozoa
Intracytoplasmic sperm injection
what technique
ratio sperm to oocyte
where is it used / indication
negatives + positives
Modification of IVF using 1 sperm per oocyte.
Indicated for severe male factor infertility, especially when few sperm are available
Introduced (1990s) with no safety testing or evaluation.
Likely to lead to transmission of genetic disorders of spermatogenesis but data are lacking.
-recent study showed children of this are likely to have a similar issue (low sperm production)
Success rates per cycle comparable to IVF but useful in wider range of patients.
Increasing trend to offer it preferentially. Higher fertilisation rate but not necessarily live birth rates
explain why you would want to implant the embryo either in the cleavage stage (3 d) or the blastocyst stage (4-5)
cleavage- Historically most common. Aim is to transfer embryo as soon as possible to avoid growth arrest in culture.
blastocyst- Development designed to allow selection of “best quality” embryo and maximise chances of success.
Early Embryo Viability Assessment aka EVA describe the technique
what was used before ?
recently introduced, commercial technique.
Uses incubator housed cameras to monitor development allowing assessment without removing embryo.
Embryo assessment usually performed under the microscope.
what grading methods do we use to select and embryo in the cleavage stage?
Evenness of blastomeres
Presence of fragmentation/ degradation
Number of cells
what grading methods do we use to select and embryo in the Blastocyst stage?
Blastocoel
Inner Cell Mass
Trophectoderm
look at grading system for cells
put on slide
