1B reproductive treatments Flashcards
What are the symptoms for low T?
- Loss of early morning erections
- Lower libido
- Decreased energy
- Lower frequency of shaving
How do we diagnose low T?
- at least 2 low measurements of serum T before 11am (when it’s meant to be high)
- Investigate the cause of low T
What different types of T replacement treatments are there?
- Daily- gel (e.g. Tostran)- care not to contaminate partner
- 3 weekly intramuscular injections (e.g. Sustanon)
- 3 monthly intramuscular injections (e.g. Nebido)
- Less common (implants, oral preparations)
What do we need to monitor for safety in testosterone replacement?
- increased haematocrit (risk of hyperviscosity and stroke)
- Prostate (Prostate specific antigen (PSA) levels)
How do we treat primary and secondary hypogonadism?
- Primary- hard to treat
- Secondary (deficiency of gonadotrophins i.e. hypogonadotrophic hypogoandism)- treat with gonadotrophins (i.e. LH and FSH) to induce spermatogenesis
What would LH and FSH do to testes?
- LH stimulates Leydig cells to increase intratesticular T to much higher levels than in circulation (x100)
- FSH stimulates seminiferous tubule development and spermatogenesis
Why do we avoid giving T to men desiring fertility?
For secondary hypogonadism (low sperm and T levels) in men desiring fertility, giving T would lower LH and FSH further and further reduce spermatogenesis
What do we give instead of T to men desiring fertility?
- hCG injections (which act on LH receptors)
- If no response after 6 months, add FSH injections
What is hypothalamic amenorrhoea?
When you have insufficient energy for fertility from decrease in hypothalamus function
What are the causes of hypothalamic amenorrhoea?
- Low body weight
- Excessive exercise
- Stress
- Genetic susceptibility
What is the aim of ovulation induction?
- To develop 1 ovarian follicle
- If >1 follicle develops, there’s risk of multiple pregnancy (twins/triplets) which has risks for mother and baby during pregnancy
- Ovulation induction aims to cause small increase in FSH
What are different methods to restore ovulation?
- Lifestyle/weight loss/metformin
- FSH stimulation by injection
- Letrozole (aromatase inhibitor)
- Clomiphene
How does letrozole work?
- Inhibits aromatase which converts T to E2
- E2 usually causes negative feedback on hypothalamus and pituitary gland to reduce LH and FSH production
- There’s decreased negative feedback now however due to low E2 so there’s increased FSH which stimulates follicle growth
How does clomiphene work?
- It’s called a modulator since it acts like an agonist/antagonist depending on tissue its in
- We’re interested in it being an E2 receptor antagonist- works in same way as letrozole
- Decreased negative feedback since E2 receptors are blocked → less negative feedback → more FSH → stimulation of follicle growth
What are the steps to IVF?
1) Induce growth of multiple follicles through giving large FSH dose
2) Collect eggs directly from ovary
3) Fertilise eggs in vitro by either:
- putting it in dish with sperm and naturally letting sperm fertilise egg
- ICSI (intracytoplasmic sperm injection)- take a single sperm and inject it directly into egg- usually done when there’s problem in sperm (male factor infertility)
4) Eggs grown in incubator for few days
5) After 3-5 days, we choose strongest embryo and transfer it back into endometrium of woman
What is premature ovulation?
Release of egg from follicle before we collect eggs for IVF
How do we prevent premature ovulation?
We give a hormone that suppresses LH surge. There are 2 ways of doing it:
- GnRH antagonist protocol (short protocol)
- GnRH agonist protocol (long protocol)
How does GnRH antagonist protocol work?
- Start FSH from day 2 of menstrual cycle
- At day 6 we start GnRH antagonist- will prevent LH surge
How does GnRH agonist protocol work?
- Start GnRH agonist from day 21 of previous cycle (day -7 of current cycle)
- Start FSH like usual on day 2
How can both a GnRH agonist and antagonist be used to block an LH surge?
- GnRH needs to be given in pulsatile manner to stimulate LH
- Agonist: If we give non-pulsatile continuous GnRH, we get desensitisation of GnRH receptor- causing initial flare of LH, but then LH inhibition
- So giving GnRH agonist can act like an antagonist and be used to induce LH inhibition
Antagonist is more self-explanatory- it’s preferred in cases where an immediate effect is needed
How do we mature the egg after preventing premature ovulation?
- We give LH exposure to induce oocyte maturation
- When eggs are immature, they’re at metaphase 1 and are diploid
- After being exposed to LH, they go into metaphase 2 and become haploid (can now be fertilised by sperm)
Which hormones do we give commonly to induce oocyte maturation?
- hCG- acts on LH receptors but is much longer acting than LH
- GnRH agonist is second most common
How many pregnancies are unplanned?
19-30%
What are the advantages of condoms?
- Protect against STIs
- Easy to obtain- free from clinics/no need to see a healthcare professional
- No contra-indications as with some hormonal methods