Subfertility Flashcards
Definition of subfertility
Inability for a couple to achieve clinical pregnancy after 12 months of regular unprotected sexual intercourse
Primary and secondary subfertility
Primary - no previous pregnancy
Secondary - at least one previous pregnancy
Incidence of subfertility within the general population
1 in 7 couples in the UK have trouble conceiving
- 84% of couples will get pregnant after having unprotected sexual intercourse for 1 year
Causes of male subfertility
Azospermia - no sperm seen in sample
- obstructive
- non-obstructive OR failure to stimulate spermatogenesis
Describe obstructive azospermia
Normal spermatogenesis, however there is an inability for sperm to leave in the ejaculate
Causes
- blockage in vas deferns or epididymis
- congenital absence of vas deferens (test for CF)
Describe non-obstructive azospermia
There is testicular failure (increased FSH)
- biopsy in case there are islands for spermatogenesis
Causes
- XXY karyotype (Kleinfelter’s)
- Y microdeletions
Rarely can be caused by failure of stimulation of spermatogenesis (decreased FSH)
- hypogonadotrophic hypogonadism
What are the female causes of subfertility
Ovulatory causes - hypothalamic-pituitary failure - HPO-axis dysfunction - ovarian failure Tubal causes Endometriosis related causes Unexplained subfertility
Important factors in the assessment of ovulatory subefertility
Primary or secondary
- primary is he failure of onset of ovulation by the age of 16 in women
- secondary is no menstruation for 6 months or more in a woman who previous had periods
Check ovulation
- day 21 progesterone (if cycle is regular) as progesterone increases once the egg is released
- retrospective diagnosis
Describe hypothalamic-pituitary failure as a cause of subfertility
GnRH release from the hypothalamus, or FSH/LH release from the pituitary is inhibited
Presents with amenorrhoea and shows a decreased LH and FSH on investigation
Causes of hypothalamic-pituitary failure
Unknown
Hypothalamus - weight, stress, exercise and craniopharyngioma
Pituitary - tumour, Sheehan’s syndrome and cerebral radiotherapy
Management of hypothalamic-pituitary failure
Increase BMI and decrease exercise
GnRH agonist
- pulsatile release
- mono-ovulation and increased live-birth success
Gonadotropin injections
- causes ovarian hyperstimulation, leading to multiple pregnancy
- FSH/LH
Causes of HPO-axis dysfunction as a cause of subfertility
Most common cause of anovulatory subfertility
Causes
- PCOS
- hyperprolactinaemia
hypothyroidism, hyperthyroidism and adrenal insufficiency
How is PCOS diagnosed
Rotterdam criteria (2 out of 3) - hyperandrogenism (increased testosterone or hirsutism) - anovulation - ultrasound shows features of PCO Bloods results expected - decreased FSH - increased LH - increased oestrogen - hyperprolactinaemia - increased free androgen index
How is PCOS managed
Weight reduction (10% weight loss causes an 80% increase in ovulation)
Letrozole
- aromatase inhibitor
- blocks oestrogen biosynthesis, so negative feedback loop is blocked, increasing FSH production and ovarian stimulation
- stimulates one follicle at a time, so has lower rates of multiple pregnancy
Clomiphene
- SERM (selective oestrogen receptor modulator)
- blocks E2 at pituitary (stops negative feedback)
- increases FSH and ovulation
- has a risk of ovarian hyperstimulation and ovarian cancer if used for >12 months
IVF (after GnRH analogue)
Ovarian drilling
What is ovarian failure as a cause of subfertility
It is a failure of the ovaries despite normal action by the pituitary and hypothalamus
- causes amenorrhoea
- increased FSH
- decreased E2