Fertility preservation Flashcards
Who are the main groups that are high priority for Fertility preservation
- Oncofertility: (2000 patients 0-44yrs undergoing gonadotoxic chemotherapy/radiation to gonads/brain
Youths
- exposed to high doses of cyclophosphamide: chemotherapy
- stem cell transplant for haematological conditions
- gender dysphoria
- Genetic conditions: turners (poi likely), klinefelters (azoospermia)
What is the type of freezing is used in fertility preservation now and why is it better
Vitrification (flash freezing- better outcomes than slow freezing as the method of cryopreservation as ice crystals that form in freezing can shatter in warming, damaging cytoplasm)
What is embryo freezing procedure, success rate, cost and ethical concern
Vitrification of IVF embryos at blastocyst day 5
No reduction in implantation rate (30%) compared to fresh embryo
Cost is relatively cheaper for storage compared to other IVF
Ethical concerns around who can use the embryo if the couple splits (within the consent), having a donor gamete for a patient w/out a partner
What are the ethical concerns around public funding for fertility preservation
- Equity: huge costs but only limited amount of funding - who to prioritise
- Informed Consent for childhood cancer patients - the event of their passing
- Societal pressure/ Social reasons
- Likelihood of success: relapse of certain cancers impacting the likelihood of pregnancy
What is procedure of Egg freezing-> implantation, success rate, and cost
Vitrification of oocytes: Can be Mature (M2) or immature (M1) therefore requiring invitro maturation bc no supporting cells and develop hardening of zona pellucida (associated with losses)
They require ICSI for fertilisation and cultured embryos can be re-frozen
Success rate less than embryo -16% live birth rate
Cost increased with follicle stimulation cycles needed, IVM, and subsequent ICSI, embryo culture etc
When is the best time to freeze eggs: lifetime and cycle
In order to freeze eggs need to undergo hormonal stimulation to harvest enough eggs
- When AMH is high, this indicates a larger number of eggs to be expected so its good to harvest then
- Over a lifetime, the number of frozen eggs needed to get a child increases with age
Also older eggs are more prone to aneuploidy
Therefore earlier cryopreservation is more likely to be successful however this needs to be balanced with the likelihood of being able to conceive naturally at a younger age.
However it is very unlikely to be successful if freezing eggs at 40yo so women need to be counselled appropriately.
What are the ethical concerns around egg freezing
Egg freezing has a low success rate/ guaranteed pregnancy
- concerns around funding for egg freezing for social/economic reasons (partner, financial security, career, unaware of age-fertility relationship)
Is it a pressure to continue
-equity issue around the costs of cycles, storage, ICSI, embryo culture
What is ovarian cryopreservation procedure. Is it done in NZ and what are the non -indications
Ovarian cryopreservation is cryopreservation of laparoscopic ovarian tissue which is then grafted back into the woman at the later date
20-30 women cryopreserve ovarian tissue but re-implantation is not an established procedure in NZ- no cases of thawing in NZ
Not to be used in benign conditions or for delaying childbearing
What are the risks of Ovarian cryopreservation
Risks
1. not able to determine who will conceive from their transplanted tissue as well as # and survival rate of follicles present without destroying it
- Safety concerns with transplanting tissue excised from patients with active disease - relapse (eg. leukaemia patients have higher risk) - no conclusive data
- Transgenerational effects are unknown - no data
What are the benefits of Ovarian cryopreservation
- Regaining fertility: restoring ovarian function
- Delaying onset of osteoporosis and menopausal symptoms : increase quality of life
- Pregnancy as long as the tissue is active
What are the methods of fertility preservation in Males : success rates, ethical concerns
Freeze sperm in liquid nitrogen, which has no deterioration in sperm quality - even at older ages so generally successful to fertilise.
Can be used for IUI, IVF, ICSI
Ethical concerns are around the preservation of childhood cancer patients fertility as they do not have sperm that can be harvested so need testicular tissue freezing so is an invasive procedure that they cannot give full consent. also questions of its use in the event of their passing
