06. Infertility

• infertility = failure to conceive after regular unprotected sexual intercourse for 2 years in absence of any known reproductive pathology
• female causes of infertility - > tubal obstruction, septate uterus, uterine leiomyomas
• tubal obstructions = scarring and adhesions in uterine tubes

  • increased incidence after STIs
  • diagnosed by HSG or HyCoSy
• endometriosis causes endometrial growth in ectopic sites leading to scarring
• uterine leiomyomas are benign smooth muscle tumours that develop in uterine walls and can be treated with hormone therapy or surgery
• implantation rates are far lower than fertilisation rates - most fail due to chromosomal abnormalities
• most male causes of infertility are diagnosed through semen analysis
• normozoospermic = normal sperm
• oligozoospermic = low levels of sperm
• asthenozoospermic = sperm with low motility
• teratozoospermic = sperm with poor morphology
• azoospermic = no sperm
• Y chromosomes deletions in the AZF region can lead to low sperm counts
• CBAVD = improper vas deferens development, linked to cystic fibrosis gene
• retrograde ejaculation = urethral sphincter doesn't close properly causing ejaculation into bladder

  • diabetes increases the risk
• clomiphene = anti-oestrogen taken for 5 days at beginning of cycle, reduces negative feedback leading to increased FSH -> stimulates follicles

  • must monitor number of follicles to prevent multiple pregnancies
• IUI = injecting prepared sperm into the uterus - can be washed to remove STIs

  • low success
• IVF = capacitated, motile sperm are added to oocyte and left to fertilise, then introduced back into uterus

  • ICSI = specialised form where sperm is injected into cytoplasm

  requires ovarian stimulation
• ovarian stimulation:

  • GnRH agonist (decreases GnRH receptors) or antagonist (represses) used to suppress pituitary
  • FSH added to cause follicle development
  • hCG added to mimic LH surge as binds to LH receptors
  • eggs collected before ovulation
• IVF can cause ovarian hyperstimulation syndrome = excessive response to fertility drugs -> multiple follicles produce VEGF -> increases vasculature permeability -> fluid accumulation in thoracic cavity