Assistive Reproductive Technologies Flashcards
(28 cards)
What is meant by Assistive Reproductive Technologies?
The handling of oocytes and embryos outside of the body.
When was the first IVF baby born?
1978
What is the brief overview of IVF?
Mature eggs are removed, fertilised in vitro, and allowed to develop to the blastocyst stage before implantation into the uterus.
How many IVF treatment cycles were there between 1991 and 2016?
Over 1 million
What are the IVF success rates like?
- Steady improvement over time.
- Current success rate is ~40% for women aged 18–34.
- Success rates decrease significantly after age 40.
What are the stages of IVF treatment?
- Suppression of Natural Cycle:
- Fertility drugs override the hypothalamic-pituitary-gonadal (HPG) axis. - Ovarian Stimulation:
- High doses of FSH stimulate multiple follicle development, with the goal of obtaining 15–16 mature oocytes. - Prevention of Premature Ovulation: - Additional drugs suppress ovulation, allowing retrieval via syringe aspiration.
- Egg Retrieval:
- Surgical removal of oocytes from the ovaries. - Sperm Preparation:
- Sperm undergoes incubation in media that mimics the female reproductive tract to induce capacitation. - Fertilisation:
- Co-incubation of oocytes and sperm in vitro.
- Monitoring of fertilised embryos to select the healthiest ones.
- Embryos develop to the blastocyst stage before implantation.
How many embryos are transferred in IVF?
- In the past , multiple embryos were transferred to increase success.
- Due to risks of multiple pregnancies, now typically only two blastocysts are transferred
What is In vitro maturation? (IVM)
- Similar to IVF but oocytes are harvested earlier before final maturation.
- Maturation occurs in vitro in the presence of FSH.
Who is IVM good for and why?
- Reduces the need for high-dose ovarian stimulation drugs.
- Beneficial for PCOS patients to avoid ovarian hyperstimulation syndrome (OHSS).
What is Intracytoplasmic sperm injection (ICSI)?
- Similar to IVF but involves direct injection of a single sperm into the oocyte.
- Often the first-line treatment in American clinics (financial reasons).
Why is ICSI used?
- Bypasses natural selection, allowing use of non-motile sperm.
- Used for male infertility, including azoospermia (lack of sperm in ejaculate).
What are the concerns with ICSI?
- Higher incidence of developmental abnormalities.
- Used with late-stage spermatids from testicular biopsies.
- Early research showed low live birth rates (3 out of 36 in early studies).
What is Gamete Intra-Fallopian Transfer? (GIFT)
- Follows IVF steps up to oocyte retrieval.
- Eggs and sperm are co-incubated and immediately transferred into fallopian tubes, allowing fertilisation to occur in vivo.
- Used for cultural/religious reasons, as fertilisation happens inside the body.
What is Zygote Intra-Fallopian Transfer? (ZIFT)
Similar to GIFT but involves in vitro fertilisation before transferring the zygote into the fallopian tubes.
When was cryopreservation first seen to be used and successful?
1953: First human birth from frozen sperm.
1985: First birth from frozen oocyte.
What were the previous and current methods for cryopreservation?
- Originally used slow freezing to maintain cell integrity.
- Now uses vitrification (rapid freezing) for better survival rates.
How much have frozen IVF treatments increased since 2013?
93%
Who is gamete freezing popular for?
- Gamete freezing is popular among people delaying parenthood or undergoing chemotherapy.
- No evidence suggests frozen embryos are of lower quality than fresh ones.
What was Cytoplasmic Transfer used for? (CT)
- Developed to treat infertility but later banned due to developmental abnormalities and miscarriages.
- 50 children were born using this method before restrictions were imposed.
What was the process of CT?
- Process follows ICSI, but involves cytoplasm transfer from a donor oocyte to a patient’s egg.
- Donor ooplasm, containing mitochondrial DNA (mtDNA), is injected into the recipient’s egg.
- Results in a heteroplasmic child (mixed mitochondrial DNA from two sources).
What is Mitochondrial Transfer? (MT)
- Legalised in the UK in 2015; not widely approved elsewhere.
- Used to prevent mitochondrial disease transmission by replacing defective mtDNA with healthy donor mtDNA.
What is the Spindle Transfer technique for MT?
- The maternal spindle (genetic material) is transferred to a donor oocyte before fertilisation.
What is the Pronuclear technique for MT?
- Both patient and donor eggs are fertilised, then the patient’s pronuclei are transferred into the donor embryo.
Why is there active research for MT?
- due to questions on mtDNA inheritance across generations.
- worries about mutated mtDNA still being present in the genome/phenotype
