Assisted Reproduction Flashcards
How do we make a woman have enough viable oocytes during assisted reproduction? At what point during the cycle?
- Inject with FSH to promote follicle growth
- Inject with LH antagonist to prevent ovulation
(Do this for the first two weeks of the cycle)
How do we monitor to ensure growth of follicles is working during assisted reproduction?
- Oestrogen and progesterone are measured every two days
- Follicle number and size are measured via ultrasound
What hormone is used to stimulate ovulation in assisted reproduction? Why might that be? How soon before egg pickup does this occur?
- hCG is used
- Has similar effects to LH, but may not be antagonised by all the LH antagonists that’ve just been pumped into the system
- Occurs 36 hours before egg pickup
What are the three ways of surgically retrieving sperm?
- Aspirating sperm from testicle
- Testicle biopsy
- Aspirating sperm from epididymis
ICSI vs IVF
- IVF: pipette sperm near egg
- ICSI: inject a single sperm cell into the egg
What can happen to embryos post-IVF?
- They can be frozen for later use (huge if true)
- They can be implanted straight into the patient at the next cycle
How are embryos frozen?
Water replaced with antifreeze
How do we tell if a patient is ovulating on their own? (Using cycle length and blood markers)
- If cycle is between 25-35, likely ovulating
- Day 21 progesterone is also a good marker
- Blood tests can also tell LH and FSH
HIgh/normal/low egg number causes of anovulation
High egg:
- PCOS (insulin stops FSH causing egg growth)
- Hypothalamic dysfunction/hypogonadism
- Athletic amenorrhoea
Normal egg:
- Hyperprolactinaemia
- Thyroid disorders
- Adrenal disorders
Low egg numbers:
- Primary ovarian insufficiency
- Peri-menopaise
How does clomiphine induce ovulation?
- Selective oestrogen receptor modulator
- Blocks negative feedback of oestrogen on hypothalamus
- Allows more FSH to be produced, meaning a follicle can be grown and ovulated (triggers positive feedback flip)
How do aromatase inhibitors (like letrozole) induce ovulation? What condition might we use them in w/ regards to female fertility?
- Block conversion of testosterone to oestrogen
- Less negative feedback on hypothalamus
- FSH increases
- By the time that oestrogen is high enough to flip feedback loop and trigger ovulation through LH, we’ve had far more FSH in the system, hence more likely effective ovulation
We might use these in settings like PCOS, where people otherwise have a hard time ovulating.
What are the risks of ovulation stimulation?
- Higher likelihood of twins, and (rarely) triplets [risk much higher during FSH rather than clomid or letrozole)
- Rarely, ovarian hyperstimulation syndrome (various changes to gut, lungs, and vasoactive factors released in larger amounts when many follicles ovulate at once)
How does ovarian hyperstimulation cause ascites?
- Follicles promote growth of blood vessels, that can leak
- When many follicles grow, many leak
- Fluid in abdo cavity = ascites
How does in vitro oocyte maturation occur? (High tech)
- FSH/LH antagonists are given as usual to promote follicle growth
- No hG is given; instead, cumulus-oocyte complex is directly aspirated, and then matured in vitro (glass), then reimplanted
Pros and Cons of In Vitro Oocyte maturation (IVM)?
Pros:
- Cheaper
- Reduced risk of ovarian hyperstimulation syndrome (no ovulation/vasoactive factors etc)
Cons:
- Fewer embryos are produced (since each need to be individually matured; ?resource constraints)
How does mitochondrial supplementation work in assisted reproduction?
- Autologous (same person) mitochondria taken from other cells, such as ovarian cells/fibroblasts
What is one advantage/disadvantage of mitochondrial supplementation fertility tech?
Adv: allows for donor mitochondria to avoid replacement (maybe, not proven)
Disadv: safety/benefit not proven
Approx efficacy of ovulation induction/ovarian stimulation
24-34%, depending on exact technique (clomid vs letrozole etc.)
Adverse effects of letrozole and clomid
- Hot flushes
- Headache
- Fatigue
- Dizziness
- Endometrial thinning (only clomid)
- Multiple pregnancies
Risks of ovarian stimulation
- Injection site reaction
- Abdo bloating/discomfort
- Ovarian hyperstimulation syndrome (what is this?)
- Multiple pregnancy
How does IVF success rate change with age?
Peaks around 48%/1 cycle at 30/31, down to almost zero in the mid forties
True or false: IVF increases risk of birth defects
True
