Reproductive treatments Flashcards
How do LH and FSH stimulate spermatogenesis?
LH stimulates Leydig cells to increase intratesticular testosterone FSH stimulates seminiferous tubule development and spermatogenesis
what is the treatment for secondary hypogonadism in men requiring fertility?
Give hCG injections which act on LH receptors If no response after 6 months, add LH injections
what treatment should you give to a man with kallmann syndrome (congenital hypogonadotrophic hypogonadism)? What pretreatment testicular size has a better outcome?
FSH for 2-4 months then hCG treatment >6ml
How does someone qualify for testosterone replacement?
at least 2 low measurements of serum testosterone before 11am
what forms of testosterone replacement are there?
daily gel eg. tostran 3 weekly IM injection (sustanon) 3 monthly IM injection (nedbido) implants, oral preparations (less common)
what precautions should be taken with tostran (daily testosterone gel)
be careful not to contaminate partner
What are the safety cautions of taking testosterone?
Increased haematocrit (risk of hyperviscosity and stroke) Prostate specific antigen levels
Why do we only want to develop one follicle during ovarian induction in PCOS?
if >1 follicle develops, this risks multiple pregnancy with more risk
How do you restore ovulation in anovulatory PCOS?
- Lifestyle/weight loss/metformin 2. Letrozole (aromatase inhibitor) reduces oestradiol to reduce negative feedback 3. Clomiphene - oestradiol receptor antagonist 4. FSH stimulation
How does letrazole, an aromatase inhibitor, affect the gonadohypothalamopituitary axis?
Inhibits conversion of testosterone to oestradiol Oestradiol normally has a negative feedback effect on the hypothalamus and anterior pituitary By reducing oestradiol we are reducing negative feedback, therefore increasing release of GnRH and LH and FSH FSH stimulates follicle growth
how does clomiphene (an oestradiol receptor antagonist) affect the gonado-hypothalamo-pituitary axis?
Works as an antagonist of the oestradiol receptors, reducing negative feedback of oestradiol (blinds the receptors to oestradiol), resulting in increased GnRH and FSH/LH, increased FSH stimulates follicle growth
What are the 4 stages of IVF treatment?
- FSH injection and oocyte retrieval
- Fertilisation in vitro
- Embryo incubation
- Embryo transfer
What two types of in vitro fertilisation are there?
Intra-cytoplasmic sperm injection (if problem with sperm)
In vitro fertilisation (standard)
What are the two types of treatment that are used to prevent LH surge and premature ovulation?
- GnRH antagonist given on day 6 of IVF (or day 5 of FSH treatment)
- GnRH agonist given 8 days before FSH treatment and maintained for duration of treatment
How can both a GnRH agonist and antagonist be used to block an LH surge?
GnRH is pulsatile
If you give a non-pulsatile GnRH agonist continuous high dose, there will be an initial flare and then LH inhibition due to desensitization of LH receptors
How are the eggs carefully matured?
By hCG exposure
What are the symptoms of ovarian hyper-stimulation syndrome and what is it caused by?
- pleural effusion
- ascites
- renal failure
- ovarian torsion
hCG injection - hCG is very long lasting and can cause this side effect
how does hCG work to cause egg maturation?
Why do we use it instead of LH?
acts on LH receptors
It is more effective and more likely to result in pregnancy
What are the barrier methods of contraception?
male/female condom/ diaphragm or cap with spermicide
what are the hormonal methods of contraception?
combined oral contraceptive pill
progestogen-only pill
long acting reversible contraception (LARC)
emergency contraception
what are the permanent methods of contraception?
Vasectomy
Female sterilisation
How does the oral contraceptive pill work?
oestrogen provides negative feedback to hypothalamopituitary axis, decreasing GnRH and LH/FSH, resulting in anovulation
progesterone thins endometrial lining and thickens cervical mucus to reduce implantation and prevent sperm entering
what are the benefits of the combined oral contraceptive pill?
One pill a day
effective
doesn’t interrupt sex
reduce endometrial and ovarian cancer
can take several packets back to back and avoid withdrawal bleeds
weight neutral in 80%
what are the downsides of the combined oral contraceptive pill?
- No protection against STIs
- Difficult to remember
- P450 enzyme inducers eg. antibiotics, may reduce efficacy
- Not great during breastfeeding
- side effects such as spotting, nausea, sore breasts, changes in mood and libido, feeling hungry